[docs] Merge neic-sda

[nanjiangshu]

Please describe the feature

As a SDA developer, I want move move the documentation from old repo to this repo so that the docs and code are at the same location.

Acceptance criteria

• Make good choices regarding github actions.
• Archive the old repository.
• Update readthedocs so it builds from the new one. Someone at the team may have credentials/rights to do this.

Additional context

• The old repository already follows the readthedocs files structure.
• There's already a branch in this repository where most of the work has been done, merge_neic-sda

Estimation of size

medium

Estimation of priority

medium