Serve webserver static files by CDN

### Description

Add a new config like STATIC_PATH to serve static files from the CDN.
Right now, static files are served with gunicorn process, while this works, I find it unnecessary makes the webserver slower. Especially with more users it requires more gunicorn processes to handle.

### Use case/motivation

Require more web servers when under the load.

### Related issues

_No response_

### Are you willing to submit a PR?

- [X] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow this project's [Code of Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)

No files, tests, or entry points are named. Start by locating the webserver's static-file serving and configuration, then determine how a STATIC_PATH-like setting would route those files to a CDN. Done means static assets no longer consume gunicorn capacity.

Written by the indexing model from the issue text.