.github: use workflow calls to build and test

Redesign how GH actions are triggered. This new design uses a
self-trigger to start jobs which are only started via workflow_calls.

The main benefit of this is to be able to start workflows from various
Infix Spins without needing to duplicate the workflow files in them.

Upcoming patches are intended to parameterize to allow Spins to pass
different architectures, brand names and such.

Signed-off-by: Richard Alpe <richard@bit42.se>

.github/workflows/trigger.yml

@@ -0,0 +1,32 @@
+name: Self Trigger
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, labeled]
+  push:
+    branches:
+      - main
+      - ci-workflow-redesign
+  workflow_dispatch:
+
+jobs:
+  build-x86_64:
+    uses: ./.github/workflows/build.yml
+    with:
+      target: x86_64 
+
+  build-aarch64:
+    uses: ./.github/workflows/build.yml
+    with:
+      target: aarch64 
+
+  test-run-x86_64:
+    needs: build-x86_64
+    uses: ./.github/workflows/test.yml
+    with:
+      target: x86_64 
+
+  test-publish-x86_64:
+    needs: test-run-x86_64
+    uses: ./.github/workflows/publish.yml
+