[CI] Refactor CI actions, use sub-actions, matrices.

.github/actions/godot-build/action.yml

@@ -0,0 +1,36 @@
+name: Build Godot
+description: Build Godot with the provided options.
+inputs:
+  target:
+    description: The scons target (debug/release_debug/release).
+    default: "debug"
+  tools:
+    description: If tools are to be built.
+    default: false
+  tests:
+    description: If tests are to be built.
+    default: false
+  platform:
+    description: The Godot platform to build.
+    required: false
+  sconsflags:
+    default: ""
+  scons-cache:
+    description: The scons cache path.
+    default: "${{ github.workspace }}/.scons-cache/"
+  scons-cache-limit:
+    description: The scons cache size limit.
+    default: 4096
+runs:
+  using: "composite"
+  steps:
+    - name: Scons Build
+      shell: sh
+      env:
+          SCONSFLAGS: ${{ inputs.sconsflags }}
+          SCONS_CACHE: ${{ inputs.scons-cache }}
+          SCONS_CACHE_LIMIT: ${{ inputs.scons-cache-limit }}
+      run: |
+        echo "Building with flags:" ${{ env.SCONSFLAGS }}
+        scons p=${{ inputs.platform }} target=${{ inputs.target }} tools=${{ inputs.tools }} tests=${{ inputs.tests }} --jobs=2 ${{ env.SCONSFLAGS }}
+        ls -l bin/

.github/actions/godot-cache/action.yml

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+name: Setup Godot build cache
+description: Setup Godot build cache.
+inputs:
+  cache-name:
+    description: The cache base name (job name by default).
+    default: "${{github.job}}"
+  scons-cache:
+    description: The scons cache path.
+    default: "${{github.workspace}}/.scons-cache/"
+runs:
+  using: "composite"
+  steps:
+    # Upload cache on completion and check it out now
+    - name: Load .scons_cache directory
+      uses: actions/cache@v2
+      with:
+        path: ${{inputs.scons-cache}}
+        key: ${{inputs.cache-name}}-${{env.GODOT_BASE_BRANCH}}-${{github.ref}}-${{github.sha}}
+        restore-keys: |
+          ${{inputs.cache-name}}-${{env.GODOT_BASE_BRANCH}}-${{github.ref}}-${{github.sha}}
+          ${{inputs.cache-name}}-${{env.GODOT_BASE_BRANCH}}-${{github.ref}}
+          ${{inputs.cache-name}}-${{env.GODOT_BASE_BRANCH}}

.github/actions/godot-deps/action.yml

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+name: Setup python and scons
+description: Setup python, install the pip version of scons.
+inputs:
+  python-version:
+    description: The python version to use.
+    default: "3.x"
+  python-arch:
+    description: The python architecture.
+    default: "x64"
+runs:
+  using: "composite"
+  steps:
+    # Use python 3.x release (works cross platform)
+    - name: Set up Python 3.x
+      uses: actions/setup-python@v2
+      with:
+        # Semantic version range syntax or exact version of a Python version
+        python-version: ${{ inputs.python-version }}
+        # Optional - x64 or x86 architecture, defaults to x64
+        architecture: ${{ inputs.python-arch }}
+
+    - name: Setup scons
+      shell: bash
+      run: |
+        python -c "import sys; print(sys.version)"
+        python -m pip install scons
+        scons --version

.github/actions/upload-artifact/action.yml

@@ -0,0 +1,19 @@
+name: Upload Godot artifact
+description: Upload the Godot artifact.
+inputs:
+  name:
+    description: The artifact name.
+    default: "${{ github.job }}"
+  path:
+    description: The path to upload.
+    required: true
+    default: "bin/*"
+runs:
+  using: "composite"
+  steps:
+    - name: Upload Godot Artifact
+      uses: actions/upload-artifact@v2
+      with:
+        name: ${{ inputs.name }}
+        path: ${{ inputs.path }}
+        retention-days: 14