Simplify releases: move npm publishing to gha, consolidate scripts (#9216)

* Remove stale comment re dependency

* Move npm publishing from release.sh to GHA

* Extract js-sdk & react-sdk post release steps

* Consolidate release subproject upgrade management

.github/workflows/release.yml

@@ -0,0 +1,11 @@
+name: Release Process
+on:
+  release:
+    types: [ published ]
+concurrency: ${{ github.workflow }}-${{ github.ref }}
+jobs:
+  npm:
+    name: Publish
+    uses: matrix-org/matrix-js-sdk/.github/workflows/release-npm.yml@develop
+    secrets:
+      NPM_TOKEN: ${{ secrets.NPM_TOKEN }}