Use GitHub's CI to test builds for each OS we claim to support

Testing that each way you can run the experiment builds with the right
deps from scratch each time is tricky. GitHub Actions provide free
unlimited minutes for exactly this kind of thing so it seems like a
no-brainer [1].

[1]: https://github.com/orgs/community/discussions/70492

Author: jacob-hughes

.github/workflows/ci.yml

@@ -0,0 +1,64 @@
+name: Alloy Experiments CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  bare-metal-debian:
+    name: Bare Metal (Debian)
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Install dependencies
+        run: ./install_deps.sh --no-cpu-gov
+      - name: Run bare-metal build
+        run: make bare-metal
+
+  bare-metal-arch:
+    name: Bare Metal (Arch Linux)
+    runs-on: ubuntu-latest
+    container:
+      image: archlinux:base
+      options: --privileged
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Install sudo
+        run: pacman -Sy --noconfirm sudo
+      - name: Install dependencies
+        run: ./install_deps.sh --no-cpu-gov
+      - name: Run bare-metal build
+        run: make bare-metal
+
+  docker-quick:
+    name: Docker Quick Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and run quick container
+        run: |
+          make run-quick
+
+  docker-full:
+    name: Docker Full Test
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v3
+
+      - name: Build and run full container
+        run: |
+          make run-full
+