implement workflows for the most part

workflows fail immediately when pushing, started filling them.
"validate" currently has a placeholder, "release" is still unable to
compile due to the clang dependency.
Will fix these in the next commit.

.github/workflows/validate.yaml

@@ -0,0 +1,15 @@
+name: release
+on:
+  push:
+    branches:
+      - dev
+      - $default-branch
+  pull_request:
+    branches:
+      - dev
+      - $default-branch
+jobs:
+  tmp:
+    runs-on: ubuntu-latest
+    steps:
+      - run: echo Hello, World