DEV: add gitpod actions
xref #47790

1. Adding an action to create the base docker file. It runs when the `environment.yml` on main is updated, or at least once monthly, to catch Ubuntu security updates
2. Adding an action to create the Gitpod docker file. It runs when main is updated.

Sidenote: I'm going on a few days vacation, and will be back to test the actions next week, so I made this a draft PR for now. If someone with docker/actions experience wants to leave a quick review—awesome. When I'm back, I will be testing it with my private account until I can access a pandas docker hub account.

CC @jorisvandenbossche @mroeschke
This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. Thanks @noatamir is this still active, can you merge main and change status from draft when ready for review. Let us know when you have time to circle back to this PR and I can reopen. Closing as stale for now