Auto-GPT developer documentation 📔

Auto-GPT is an experimental project, where we want to encourage involvement and empower anyone to contribute. We also want to work based off of research and data rather than gut feelings. To enable all of this, we need better architectural and design documentation.

## TODO
~~- [ ] Make Jupyter notebooks for all of our prompting~~ No longer applicable
- [ ] Document the application's program flow (including architectural notes) in Whimsical and/or Markdown
- [ ] Add references to this new documentation in all the right places
* Contributor guide
* README
* Docs site
- [ ] Require PRs to include updates to developer docs if applicable
- [x] Add documentation delineating all components that can be used (see https://www.home-assistant.io/integrations/)
- [x] Add documentation on building agents using forge (and other autogpt components)
- [ ] Add library documentation for Platfomr and AutoGPT components
- [ ] Document supported versions of various components

Start by reading the current Contributor guide, README, and docs site, then review the existing component and Forge documentation. Map the unchecked items to the documentation gaps, especially program flow, library references, PR documentation expectations, and supported versions. Done means the selected documentation is published and linked from the relevant project entry points.

Written by the indexing model from the issue text.