SDK docs build

[discdiver]

Builds SDK docs for Prefect and all integration libraries with make docs.

The Makefile calls the serve_docs script @zzstoatzz created.

The script installs editable versions of all packages, calls the python scripts/generate_sdk_docs.py script that @chrisguidry created, and uses Mkdocs Material to build the SDK docs in the "site" folder.

The site folder can then be deployed to Netlify. Will automate that on Netlify's side next.

Example

Checklist

• [X] This pull request includes a label categorizing the change e.g. maintenance, fix, feature, enhancement, docs.
• [ ] This pull request references any related issue by including "closes <link to issue>"
  • If no issue exists and your change is not a small fix, please create an issue first.
• [ ] If this pull request adds new functionality, it includes unit tests that cover the changes
• [ ] If this pull request removes docs files, it includes redirect settings in mint.json.
• [ ] If this pull request adds functions or classes, it includes helpful docstrings.

[discdiver]

Merging with unrelated prefect-dbt failures only and an issue opened for that.