Migrate to Upbound DevEx

[ytsarev]

Description of your changes

Depends on:

• We need to label general subnet for deterministic selection configuration-azure-network#118
• Deterministically select general subnet configuration-azure-aks#105
• Propagate connection secrets with username and password configuration-azure-database#105

Associated dependency versions in upbound.yaml will be bumped to stable tags after the merge and release of the PRs above

I have:

• Read and followed Upbound's contribution process.
• Run make reviewable to ensure this PR is ready for review.
• Added backport release-x.y labels to auto-backport this PR, as appropriate.

How has this code been tested

Composition and e2e

        === COMMAND
        /bin/sh -c ${KUBECTL} wait --for=delete xapp.platform.upbound.io/platform-ref-azure-cluster-ghost --timeout 1h15m0s
    | 18:01:14 | delete | Assert Deletion  | SCRIPT    | DONE  |
    | 18:01:14 | delete | Assert Deletion  | TRY       | END   |
    | 18:01:14 | delete | @chainsaw        | CLEANUP   | SKIP  |
=== NAME  chainsaw
    | 18:01:14 | chainsaw | @chainsaw | CLEANUP   | SKIP  |
--- PASS: chainsaw (0.00s)
    --- PASS: chainsaw/delete (4.13s)
PASS
2025/06/27 18:01:14 Tests Summary:
2025/06/27 18:01:14 - Passed: 1
2025/06/27 18:01:14 - Failed: 0
2025/06/27 18:01:14 - Skipped: 0
SUCCESS:
SUCCESS: Tests Summary:
SUCCESS: ------------------
SUCCESS: Total Tests Executed: 1
SUCCESS: Passed tests:         1
SUCCESS: Failed tests:         0

crossplane beta trace xcluster.azure.platformref.upbound.io/platform-ref-azure-cluster
NAME                                                                                      SYNCED   READY   STATUS
XCluster/platform-ref-azure-cluster                                                       True     True    Available
├─ Usage/usage-xaks-by-arbitrary-labeled-release                                          -        True    Available
├─ Usage/usage-xeks-by-xflux                                                              -        True    Available
├─ Usage/usage-xeks-by-xoss                                                               -        True    Available
├─ XAKS/composite-cluster-aks                                                             True     True    Available
│  ├─ KubernetesCluster/platform-ref-azure-cluster-aks                                    True     True    Available
│  ├─ ProviderConfig/platform-ref-azure-cluster                                           -        -
│  ├─ Object/platform-ref-azure-cluster-wzp92                                             True     True    Available
│  └─ ProviderConfig/platform-ref-azure-cluster                                           -        -
├─ XNetwork/composite-network-aks                                                         True     True    Available
│  ├─ ResourceGroup/platform-ref-azure-cluster-rg                                         True     True    Available
│  ├─ Subnet/platform-ref-azure-cluster-db-sn-0                                           True     True    Available
│  ├─ Subnet/platform-ref-azure-cluster-sn                                                True     True    Available
│  └─ VirtualNetwork/platform-ref-azure-cluster-vnet                                      True     True    Available
├─ XFlux/composite-flux                                                                   True     True    Available
│  ├─ Release/release-flux                                                                True     True    Available
│  └─ Release/sync-flux                                                                   True     True    Available
└─ XOss/composite-observability-oss                                                       True     True    Available
   ├─ Usage/usageprometheusbypodmonitorcrossplane-platform-ref-azure-cluster              -        True    Available
   ├─ Usage/usageprometheusbypodmonitorcrossplanerbacmanager-platform-ref-azure-cluster   -        True    Available
   ├─ Usage/usageprometheusbypodmonitorproviders-platform-ref-azure-cluster               -        True    Available
   ├─ Release/releaseprometheus-platform-ref-azure-cluster                                True     True    Available
   ├─ Object/podmonitorcrossplane-platform-ref-azure-cluster                              True     True    Available
   ├─ Object/podmonitorcrossplaneproviders-platform-ref-azure-cluster                     True     True    Available
   └─ Object/podmonitorcrossplanerbacmanager-platform-ref-azure-cluster                   True     True    Available

[ytsarev]

@kaessert Composition and e2e tests after the dependency bump to stabled release versions:

up test run tests/*
  ✓   Parsing tests
  ✓   Checking dependencies
  ✓   Generating language schemas
  ✓   Building functions
  ✓   Building configuration package
  ✓   Pushing embedded functions to local daemon
  ✓   Assert test-xcluster
SUCCESS:
SUCCESS: Tests Summary:
SUCCESS: ------------------
SUCCESS: Total Tests Executed: 1
SUCCESS: Passed tests:         1

XApp/platform-ref-azure-cluster-ghost                             True     True    Available
└─ Release/platform-ref-azure-cluster-ghost-48kvq   helmRelease   True     True    Available
    | 01:08:28 | delete | Delete Resources | SCRIPT    | LOG   |
        === STDOUT
        xcluster.azure.platformref.upbound.io "platform-ref-azure-cluster" deleted
        xsqlinstance.azure.platform.upbound.io "platform-ref-azure-cluster-db-mysql" deleted
        xapp.platform.upbound.io "platform-ref-azure-cluster-ghost" deleted
    | 01:08:28 | delete | Delete Resources | SCRIPT    | DONE  |
    | 01:08:28 | delete | Delete Resources | TRY       | END   |
    | 01:08:28 | delete | Assert Deletion  | TRY       | BEGIN |
    | 01:08:28 | delete | Assert Deletion  | CMD       | RUN   |
        === COMMAND
        /bin/sh -c ${KUBECTL} wait --for=delete xcluster.azure.platformref.upbound.io/platform-ref-azure-cluster --timeout 1h15m0s
    | 01:08:29 | delete | Assert Deletion  | SCRIPT    | DONE  |
    | 01:08:29 | delete | Assert Deletion  | CMD       | RUN   |
        === COMMAND
        /bin/sh -c ${KUBECTL} wait --for=delete xsqlinstance.azure.platform.upbound.io/platform-ref-azure-cluster-db-mysql --timeout 1h15m0s
    | 01:08:29 | delete | Assert Deletion  | SCRIPT    | DONE  |
    | 01:08:29 | delete | Assert Deletion  | CMD       | RUN   |
        === COMMAND
        /bin/sh -c ${KUBECTL} wait --for=delete xapp.platform.upbound.io/platform-ref-azure-cluster-ghost --timeout 1h15m0s
    | 01:08:30 | delete | Assert Deletion  | SCRIPT    | DONE  |
    | 01:08:30 | delete | Assert Deletion  | TRY       | END   |
    | 01:08:30 | delete | @chainsaw        | CLEANUP   | SKIP  |
=== NAME  chainsaw
    | 01:08:30 | chainsaw | @chainsaw | CLEANUP   | SKIP  |
--- PASS: chainsaw (0.00s)
    --- PASS: chainsaw/delete (4.34s)
PASS
2025/06/28 01:08:30 Tests Summary:
2025/06/28 01:08:30 - Passed: 1
2025/06/28 01:08:30 - Failed: 0
2025/06/28 01:08:30 - Skipped: 0
SUCCESS:
SUCCESS: Tests Summary:
SUCCESS: ------------------
SUCCESS: Total Tests Executed: 1
SUCCESS: Passed tests:         1

[kaessert]

LGTM!