Admin: Repair changelog and curate docs landing.

[BrianWhitneyAI]

Description

The purpose of this PR is to resolve #164 and #163.

For #164 Our changelog command was not functioning correctly so docs were showing as blank. Additionally the old .gitchangelog.rc was outdated and brittle so I updated some of the policies.

For #163 I wanted to keep index as our landing as it simplifies our doc structure and defines the sidebar options. To capture the overview doc on landing I moved index.rst to index.md so we could insert OVERVIEW.md into the body. I think this'll be better since we can separate the content of the overview from the structuring of the docs

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.14%. Comparing base (e054d0d) to head (2d7f467).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #167   +/-   ##
=======================================
  Coverage   83.14%   83.14%           
=======================================
  Files          11       11           
  Lines         724      724           
=======================================
  Hits          602      602           
  Misses        122      122           

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