chore(ci): Add build and deploy book

.github/workflows/book.yml

@@ -0,0 +1,38 @@
+name: Build and deploy documentation book
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  book:
+    name: Build and deploy book
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          override: true
+
+      - name: Install mdbook
+        run: |
+          (test -x $HOME/.cargo/bin/cargo-install-update || cargo install cargo-update)
+          (test -x $HOME/.cargo/bin/mdbook || cargo install --vers "^0.2" mdbook)
+          cargo install-update -a
+
+      - name: Build book
+        run: |
+          mdbook --version
+          (cd docs && mv _theme theme && mdbook build)
+          rustc ./docs/_installer/build-installer.rs
+          ./build-installer
+
+      - name: Deploy book
+        uses: JamesIves/github-pages-deploy-action@4.1.4
+        with:
+          branch: gh-pages
+          folder: docs
+          token: ${{ secrets.GITHUB_TOKEN }}
+          single-commit: true