feat: rust-doc to github pages (privacy-scaling-explorations#1578)

### Description

This pull request aims to run the cargo doc in CI to generate and
publish the doc to GitHub Pages.

### Issue Link

Solving privacy-scaling-explorations#1206 

### Type of change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [X] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update

### Contents

The implementation is in _.github/workflows/github-pages.yml_.
The goal is to generate the doc, upload the doc, and deploy the page.

### How Has This Been Tested?

I have tested this in my [forked
repository](https://github.com/ryanycw/zkevm-circuits/actions/workflows/github-pages.yml).
And here is the
[demo](https://ryanycw.github.io/zkevm-circuits/zkevm_circuits/) of what
the result will look like.

---------

Co-authored-by: Chih Cheng Liang <[email protected]>

.github/workflows/github-pages.yml

@@ -0,0 +1,68 @@
+# Simple workflow for deploying static content to GitHub Pages
+name: Deploy static content to Pages
+
+on:
+  # Runs on pushes targeting the default branch
+  push:
+    branches: ['main']
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: 'pages'
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+      - uses: actions-rs/toolchain@v1
+      - name: Setup Pages
+        uses: actions/configure-pages@v3
+      # Create a index.html outside of the subdirectories for requirement of GitHub pages
+      - name: Generate Docs
+        run: |
+          cargo doc --no-deps
+          echo "<meta http-equiv=\"refresh\" content=\"0; url=zkevm_circuits\">" > target/doc/index.html
+      # Archive the artifact with the correct permissions
+      # https://github.com/actions/deploy-pages/issues/188
+      - name: Archive artifact
+        shell: sh
+        run: |
+          chmod -c -R +rX "target/doc" |
+          while read line; do
+              echo "::warning title=Invalid file permissions automatically fixed::$line"
+          done
+          tar \
+            --dereference --hard-dereference \
+            --directory "target/doc" \
+            -cvf "$RUNNER_TEMP/artifact.tar" \
+            --exclude=.git \
+            --exclude=.github \
+            .
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v2
+        with:
+          path: 'target/doc'
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v2