Docs: new documentation site (#2723)

This commit adds a VitePress build to the main repository,
aiming to ditch GitHub Wiki. Moving further, we're going to
host our own documentation site eithor on GitHub Pages or
something alike.

.github/workflows/deploy-docs.yml

@@ -0,0 +1,42 @@
+name: Deploy
+on:
+  workflow_dispatch: {}
+  push:
+    branches:
+      - master
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        node-version: [20]
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - uses: pnpm/action-setup@v2
+        with:
+          version: latest
+      - name: Use Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node-version }}
+      - name: Install dependencies
+        working-directory: docs
+        run: pnpm install --frozen-lockfile=false
+      - name: Build
+        working-directory: docs
+        run: pnpm run docs:build
+      - uses: actions/configure-pages@v2
+      - uses: actions/upload-pages-artifact@v1
+        with:
+          path: docs/.vitepress/dist
+      - name: Deploy
+        id: deployment
+        uses: actions/deploy-pages@v1