GHA CI: Backport latest changes (#15361)

By having unified github workflows, the building cache would be utilized
more efficiently as the total cache size will be smaller (no more vcpkg
caching on macOS CI) and will stop thrashing the build cache (large
vcpkg cache evicts other smaller cache).

Relevant PRs:
#15321
#15340
#15342
#15355

.github/workflows/ci_windows.yaml

@@ -0,0 +1,85 @@
+name: CI - Windows
+on: [pull_request, push]
+
+jobs:
+  ci:
+    name: Build
+    runs-on: windows-2019
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Install build tools
+        run: |
+          choco install ninja
+
+      # use the preinstalled vcpkg from image
+      # https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md#package-management
+      - name: Setup vcpkg
+        uses: lukka/run-vcpkg@v7
+        with:
+          vcpkgDirectory: C:/vcpkg
+          doNotUpdateVcpkg: true  # the preinstalled vcpkg is updated regularly
+          setupOnly: true
+
+      # tell vcpkg to only build Release variants of the dependencies
+      - name: Configure vcpkg triplet overlay
+        run: |
+          New-Item `
+            -Path "${{ github.workspace }}" `
+            -Name "triplets_overlay" `
+            -ItemType Directory
+          Copy-Item `
+            "${{ env.RUNVCPKG_VCPKG_ROOT }}/triplets/x64-windows-static.cmake" `
+            "${{ github.workspace }}/triplets_overlay/x64-windows-static-release.cmake"
+          Add-Content `
+            "${{ github.workspace }}/triplets_overlay/x64-windows-static-release.cmake" `
+            -Value "set(VCPKG_BUILD_TYPE release)"
+
+      # clear buildtrees after each package installation to reduce disk space requirements
+      - name: Install dependencies
+        run: |
+          $packages = `
+            "boost-circular-buffer:x64-windows-static-release",
+            "libtorrent:x64-windows-static-release",
+            "qt5-base:x64-windows-static-release",
+            "qt5-svg:x64-windows-static-release",
+            "qt5-tools:x64-windows-static-release",
+            "qt5-winextras:x64-windows-static-release"
+          ${{ env.RUNVCPKG_VCPKG_ROOT }}/vcpkg.exe upgrade `
+            --overlay-triplets="${{ github.workspace }}/triplets_overlay" `
+            --no-dry-run
+          ${{ env.RUNVCPKG_VCPKG_ROOT }}/vcpkg.exe install `
+            --overlay-triplets="${{ github.workspace }}/triplets_overlay" `
+            --clean-after-build `
+            $packages
+
+      # this is necessary to correctly find and use cl.exe with the Ninja generator for now
+      - name: Setup devcmd
+        uses: ilammy/msvc-dev-cmd@v1
+
+      - name: Build qBittorrent
+        run: |
+          cmake `
+            -B build `
+            -G "Ninja" `
+            -DCMAKE_BUILD_TYPE=RelWithDebInfo `
+            -DCMAKE_EXPORT_COMPILE_COMMANDS=ON `
+            -DCMAKE_TOOLCHAIN_FILE="${{ env.RUNVCPKG_VCPKG_ROOT }}/scripts/buildsystems/vcpkg.cmake" `
+            -DMSVC_RUNTIME_DYNAMIC=OFF `
+            -DVCPKG_TARGET_TRIPLET=x64-windows-static-release `
+            -DVERBOSE_CONFIGURE=ON `
+            --graphviz=build/target_graph.dot
+          cmake --build build
+
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v2
+        with:
+          name: qBittorrent-CI_Windows-x64
+          path: |
+            build/compile_commands.json
+            build/qbittorrent.exe
+            build/qbittorrent.pdb
+            build/target_graph.dot
+            dist/windows/qt.conf