Drop Python 3.8/3.9 support and remove Holography agents

[BrianJKoopman]

Note: This PR is into the v0.7.0-dev branch, not main. Keeping thing separated from main until v0.6.1 is released.

Description

This PR formally drops Python 3.8/3.9 support and removes the Holography agents (which depend on Python 3.8). It also re-adds Python 3.12 to the CI tests.

Motivation and Context

We're following the plans in ocs for v0.13.0 and dropping end of life Python versions. This also allows us to use the official published versions of some of our dependencies (namely sotodlib and sodetlib.)

Resolves #1035.

How Has This Been Tested?

This has not yet been tested. I need to see how the CI runs, hence the draft PR. I'll also do some local testing before we merge this.

I also still need to update the develop and deploy workflows to a non Python 3.8 version -- they're probably going to break for now...

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.