firefox: update 134.0.2 -> 135.0, pass yocto-check-layer

new PACKAGECONFIG: rust-simd
Enable by default.

Also remove meta-rust support, and support only meta-lts-mixins.

When the Rust version in oe-core is too old to compile Firefox, meta-lts-mixins
should be used. meta-rust uses a different target name scheme than the other layers,
so it adds some extra complexity to the recipes, which ultimately isn't required
now that the mixins layers have full support for Firefox.

Remove unneeded llvm patches:

The fix has been included in clang since version 18.1.
Scarthgap uses 18.1.3
Styhead uses 19.1.2
Walnascar uses 19.1+
Risc-V is not tested with Kirkstone

The last patch that fixed the compilation with clang 12 (on Kirkstone)
has been merged in meta-clang, the patch is not required anymore in
this repository.

To pass the yocto-check-layer tests, the following changes were needed:

1. Add SECURITY.md with information on reporting security vulnerabilities.
2. Add info about contribution in README.md (it was already there, but the
test script is very particular about including the word "patch")
3. Update cbindgen recipe to the latest version (to not clash with the
one meta-oe. Though most probably this only passes in Walnascar now.
However in other meta-oe branches this is an update, not a downgrade)

Author: OldManYellsAtCloud

.github/workflows/kirkstone-aarch64-v134.0.2.yml renamed to .github/workflows/kirkstone-aarch64-v135.0.yml

@@ -1,4 +1,4 @@
-name: kirkstone-aarch64-134.0.2
+name: kirkstone-aarch64-135.0
 run-name: Build latest Firefox for 64-bit ARM architecture with Kirkstone
 on:
   pull_request:

.github/workflows/kirkstone-arm-v134.0.2.yml renamed to .github/workflows/kirkstone-arm-v135.0.yml

@@ -1,4 +1,4 @@
-name: kirkstone-arm-134.0.2
+name: kirkstone-arm-135.0
 run-name: Build latest Firefox for 32-bit ARM architecture with Kirkstone
 on:
   pull_request:

.github/workflows/kirkstone-x86_64-v134.0.2.yml renamed to .github/workflows/kirkstone-x86_64-v135.0.yml

@@ -1,4 +1,4 @@
-name: kirkstone-x86_64-134.0.2
+name: kirkstone-x86_64-135.0
 run-name: Build latest Firefox for x86_64 architecture with Kirkstone
 on:
   pull_request:

.github/workflows/scarthgap-aarch64-v134.0.2.yml renamed to .github/workflows/scarthgap-aarch64-v135.0.yml

@@ -1,4 +1,4 @@
-name: scarthgap-aarch64-134.0.2
+name: scarthgap-aarch64-135.0
 run-name: Build latest Firefox for 64-bit ARM architecture with Scarthgap
 on:
   pull_request:

.github/workflows/scarthgap-arm-v134.0.2.yml renamed to .github/workflows/scarthgap-arm-v135.0.yml

@@ -1,4 +1,4 @@
-name: scarthgap-arm-134.0.2
+name: scarthgap-arm-135.0
 run-name: Build latest Firefox for 32-bit ARM architecture with Scarthgap
 on:
   pull_request:

.github/workflows/scarthgap-riscv-v134.0.2.yml renamed to .github/workflows/scarthgap-riscv-v135.0.yml

@@ -1,4 +1,4 @@
-name: scarthgap-riscv-134.0.2
+name: scarthgap-riscv-135.0
 run-name: Build latest Firefox for Risc-V architecture with Scarthgap
 on:
   pull_request:

.github/workflows/scarthgap-x86_64-v134.0.2.yml renamed to .github/workflows/scarthgap-x86_64-v135.0.yml

@@ -1,4 +1,4 @@
-name: scarthgap-x86_64-134.0.2
+name: scarthgap-x86_64-135.0
 run-name: Build latest Firefox for x86_64 architecture with Scarthgap
 on:
   pull_request:

.github/workflows/styhead-aarch64-v134.0.2.yml renamed to .github/workflows/styhead-aarch64-v135.0.yml

@@ -1,4 +1,4 @@
-name: styhead-aarch64-134.0.2
+name: styhead-aarch64-135.0
 run-name: Build latest Firefox for 64-bit ARM architecture with Styhead
 on:
   pull_request:

.github/workflows/styhead-arm-v134.0.2.yml renamed to .github/workflows/styhead-arm-v135.0.yml

@@ -1,4 +1,4 @@
-name: styhead-arm-134.0.2
+name: styhead-arm-135.0
 run-name: Build latest Firefox for 32-bit ARM architecture with Styhead
 on:
   pull_request:

.github/workflows/styhead-riscv-v134.0.2.yml renamed to .github/workflows/styhead-riscv-v135.0.yml

@@ -1,4 +1,4 @@
-name: styhead-riscv-134.0.2
+name: styhead-riscv-135.0
 run-name: Build latest Firefox for Risc-V architecture with Styhead
 on:
   pull_request: