Add CI for tests and CD for docs deployment

- Added `.github/workflows/ci.yml` to run tests on Python 3.10 and 3.11.
- Added `.github/workflows/deploy-docs.yml` to deploy mkdocs to gh-pages with git user configuration.
- Updated `pyproject.toml` to include `mkdocs-material` dependency.
- Updated `mkdocs.yml` to use `material` theme.
- Added `site/` to `.gitignore`.
- Fixed CI error by removing `submodules: recursive` (broken submodule references).
- Removed broken gitlinks/submodules from repository index.

Author: google-labs-jules[bot]

.github/workflows/deploy-docs.yml

@@ -19,5 +19,9 @@ jobs:
       - name: Install dependencies
         run: |
           pip install .
+      - name: Configure Git User
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
       - name: Deploy
         run: mkdocs gh-deploy --force