doc: Add gitaction workflow for building docs

Author: tjora

.github/workflows/docs.yml

@@ -0,0 +1,70 @@
+# Copyright (c) 2024, Nordic Semiconductor ASA
+# SPDX-License-Identifier: Apache-2.0
+
+name: Documentation
+
+on: [push, pull_request]
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    name: Build
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        doxygen-version: [1.9.6, 1.14.0]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+
+      - name: Install dependencies
+        run: |
+          DOXYGEN_VERSION="${{ matrix.doxygen-version }}"
+          wget --no-verbose "https://github.com/doxygen/doxygen/releases/download/Release_${DOXYGEN_VERSION//./_}/doxygen-${DOXYGEN_VERSION}.linux.bin.tar.gz"
+          tar xf doxygen-${DOXYGEN_VERSION}.linux.bin.tar.gz
+          echo "${PWD}/doxygen-${DOXYGEN_VERSION}/bin" >> $GITHUB_PATH
+          pip install -r doc/requirements.txt
+
+      - name: Build
+        run: |
+          cd doc
+          doxygen
+
+          SPHINXOPTS="-W" make html
+
+          mkdir deploy
+          mv _build_doxygen/html deploy/doxygen
+          mv _build_sphinx/html/* deploy
+
+      - name: Setup pages
+        if: github.event_name != 'pull_request' && matrix.doxygen-version == '1.14.0'
+        uses: actions/configure-pages@v4
+
+      - name: Upload pages artifact
+        if: github.event_name != 'pull_request' && matrix.doxygen-version == '1.14.0'
+        uses: actions/upload-pages-artifact@v3
+        with:
+          path: doc/deploy
+
+      - name: Upload artifacts
+        if: github.event_name == 'pull_request'
+        uses: actions/upload-artifact@v4
+        with:
+          name: docs-doxygen-${{ matrix.doxygen-version }}
+          path: doc/deploy
+
+  deploy:
+    name: Deploy
+    runs-on: ubuntu-22.04
+    needs: build
+    if: github.event_name != 'pull_request'
+    permissions:
+      pages: write
+      id-token: write
+    steps:
+      - name: Deploy to GitHub Pages
+        uses: actions/deploy-pages@v4