Fixing #1009 Doc upgrade/downgrade policy

- Add section on upgrading/downgrading and boot-order to system.md
- Add or update references on upgrading from other pages
  - boot.md (update ref)
  - cli/upgrade.md (add ref)
  - management.md (add ref)

[skip ci]

Author: jovatn

doc/ChangeLog.md

@@ -10,6 +10,7 @@ All notable changes to the project are documented in this file.
 - Upgrade libyang to 3.12.2
 - Upgrade sysrepo to 3.6.11
 - Upgrade netopeer2 (NETCONF) to 2.4.1
+- Add documentation on Infix upgrading and downgrading, issue #1009
 
 ### Fixes
 

doc/boot.md

@@ -349,5 +349,6 @@ can funtion reasonably well without a persistent `/var`, loosing
 If `var` is not available, Infix will still persist `/var/lib` using
 `cfg` as the backing storage.
 
-[^1]: See [CLI Upgrade](cli/upgrade.md) for information on upgrading
-    via CLI.
+[^1]: See [Upgrading procedures and boot
+    order](system.md#upgrade-procedures-and-boot-order) for
+    information on upgrading via CLI.

doc/cli/upgrade.md

@@ -39,7 +39,12 @@ The secondary partition (`rootfs.1`) has now been upgraded and will be used as
 the *active* partition on the next boot.  Leaving the primary partition, with
 the version we are currently running, intact in case of trouble.
 
+See [upgrading procedures and boot order][2] for more information on
+    upgrading.
+
 [^1]: It is not possible to upgrade the partition we booted from.  Thankfully
     the underlying "rauc" subsystem keeps track of this.  Hence, to upgrade
     both partitions you must reboot to the new version (to verify it works)
     and then repeat the same command.
+
+[2]: ../system.md#upgrade-procedures-and-boot-order

doc/management.md

@@ -193,3 +193,11 @@ admin@example:/config/web/> edit restconf
 admin@example:/config/web/restconf/> no enabled
 admin@example:/config/web/restconf/>
 ```
+
+# System Upgrade
+
+See [upgrading procedures and boot order][1] for information on
+    upgrading.
+
+
+[1]: system.md#upgrade-procedures-and-boot-order