Add cmake-format config

Improve formatting.
Use Tabs.
Make copyright one whole comment block.
Remove spaces inside of functions and after if.
Remove excessive whitespace.
Add github action to validate formatting.

.github/workflows/format.yml

@@ -0,0 +1,55 @@
+# https://github.com/openblack/bgfx.cmake/blob/master/.github/workflows/format.yml
+name: Format
+
+on:
+  push:
+    branches: [ master ]
+  pull_request_target:
+    branches: [ master ]
+
+jobs:
+  job:
+    cmake-format-check:
+    name: cmake-format
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+      - name: Add base repo to git config
+        run: git remote add upstream ${{ github.event.pull_request.base.repo.html_url }}
+        if: startsWith(github.event_name, 'pull_request')
+      - name: Format CMake files
+        id: cmake-format
+        uses: PuneetMatharu/cmake-format-lint-action@main
+        with:
+          args: --config-files .cmake-format.py --check
+  # Run only if a PR and cmake-format has failed
+  cmake-format-action-suggester:
+    name: cmake-format fix suggester
+    runs-on: ubuntu-latest
+    needs: cmake-format-check
+    if: always() && startsWith(github.event_name, 'pull_request') && needs.cmake-format-check.result == 'failure'
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          ref: ${{ github.event.pull_request.head.ref }}
+          repository: ${{ github.event.pull_request.head.repo.full_name }}
+      - name: Add base repo to git config
+        run: git remote add upstream ${{ github.event.pull_request.base.repo.html_url }}
+        if: startsWith(github.event_name, 'pull_request')
+      - name: Format CMake files
+        id: cmake-format
+        uses: PuneetMatharu/cmake-format-lint-action@v1.0.0
+        with:
+          args: --config-files .cmake-format.py --in-place
+      - run: |
+          git diff > cmake-format.patch
+      - uses: actions/upload-artifact@v2
+        with:
+          name: formatting-fix-${{github.sha}}
+          path: cmake-format.patch
+      - uses: reviewdog/action-suggester@v1
+        with:
+          tool_name: cmake-format