feat(ci): don't build storage on compute-releases and vice versa (#10841)

## Problem
Release CI is slow, because we're doing unnecessary work, for example
building compute images on storage releases and vice versa.

## Summary of changes
- Extract tag generation into reusable workflow and extend it with
fetching of previous component releases
- Don't build neon images on compute releases and don't build compute
images on proxy and storage releases
- Reuse images from previous releases for tests on branches where we
don't build those images

## Open questions
- We differentiate between `TAG` and `COMPUTE_TAG` in a few places, but
we don't differentiate between storage and proxy releases. Since they
use the same image, this will continue to work, but I'm not sure this is
what we want.

.github/workflows/trigger-e2e-tests.yml

@@ -5,6 +5,10 @@ on:
     types:
       - ready_for_review
   workflow_call:
+    inputs:
+      github-event-name:
+        type: string
+        required: true
 
 defaults:
   run:
@@ -19,7 +23,7 @@ jobs:
     if: ${{ !contains(github.event.pull_request.labels.*.name, 'run-no-ci') }}
     uses: ./.github/workflows/check-permissions.yml
     with:
-      github-event-name: ${{ github.event_name }}
+      github-event-name: ${{ inputs.github-event-name || github.event_name }}
 
   cancel-previous-e2e-tests:
     needs: [ check-permissions ]
@@ -35,46 +39,29 @@ jobs:
             run cancel-previous-in-concurrency-group.yml \
               --field concurrency_group="${{ env.E2E_CONCURRENCY_GROUP }}"
 
-  tag:
-    needs: [ check-permissions ]
-    runs-on: ubuntu-22.04
-    outputs:
-      build-tag: ${{ steps.build-tag.outputs.tag }}
-
-    steps:
-      # Need `fetch-depth: 0` to count the number of commits in the branch
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-
-      - name: Get build tag
-        env:
-          GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
-          CURRENT_BRANCH: ${{ github.head_ref || github.ref_name }}
-          CURRENT_SHA: ${{ github.event.pull_request.head.sha || github.sha }}
-        run: |
-          if [[ "$GITHUB_REF_NAME" == "main" ]]; then
-            echo "tag=$(git rev-list --count HEAD)" | tee -a $GITHUB_OUTPUT
-          elif [[ "$GITHUB_REF_NAME" == "release" ]]; then
-            echo "tag=release-$(git rev-list --count HEAD)" | tee -a $GITHUB_OUTPUT
-          elif [[ "$GITHUB_REF_NAME" == "release-proxy" ]]; then
-            echo "tag=release-proxy-$(git rev-list --count HEAD)" >> $GITHUB_OUTPUT
-          elif [[ "$GITHUB_REF_NAME" == "release-compute" ]]; then
-            echo "tag=release-compute-$(git rev-list --count HEAD)" >> $GITHUB_OUTPUT
-          else
-            echo "GITHUB_REF_NAME (value '$GITHUB_REF_NAME') is not set to either 'main' or 'release'"
-            BUILD_AND_TEST_RUN_ID=$(gh run list -b $CURRENT_BRANCH -c $CURRENT_SHA -w 'Build and Test' -L 1 --json databaseId --jq '.[].databaseId')
-            echo "tag=$BUILD_AND_TEST_RUN_ID" | tee -a $GITHUB_OUTPUT
-          fi
-        id: build-tag
+  meta:
+    uses: ./.github/workflows/_meta.yml
+    with:
+      github-event-name: ${{ inputs.github-event-name || github.event_name }}
 
   trigger-e2e-tests:
-    needs: [ tag ]
+    needs: [ meta ]
     runs-on: ubuntu-22.04
     env:
       EVENT_ACTION: ${{ github.event.action }}
       GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
-      TAG: ${{ needs.tag.outputs.build-tag }}
+      TAG: >-
+        ${{
+          contains(fromJSON('["compute-release", "compute-rc-pr"]'), needs.meta.outputs.run-kind)
+          && needs.meta.outputs.previous-storage-release
+          || needs.meta.outputs.build-tag
+        }}
+      COMPUTE_TAG: >-
+        ${{
+          contains(fromJSON('["storage-release", "storage-rc-pr", "proxy-release", "proxy-rc-pr"]'), needs.meta.outputs.run-kind)
+          && needs.meta.outputs.previous-compute-release
+          || needs.meta.outputs.build-tag
+        }}
     steps:
       - name: Wait for `push-{neon,compute}-image-dev` job to finish
         # It's important to have a timeout here, the script in the step can run infinitely
@@ -157,6 +144,6 @@ jobs:
               --raw-field "commit_hash=$COMMIT_SHA" \
               --raw-field "remote_repo=${GITHUB_REPOSITORY}" \
               --raw-field "storage_image_tag=${TAG}" \
-              --raw-field "compute_image_tag=${TAG}" \
+              --raw-field "compute_image_tag=${COMPUTE_TAG}" \
               --raw-field "concurrency_group=${E2E_CONCURRENCY_GROUP}" \
               --raw-field "e2e-platforms=${E2E_PLATFORMS}"