[DOC] Add development section to the docs

[beeme1mr]

Change in the documentation

Create a new section in the docs that focuses on development.

The structure could like something like this:

• Development
  • Integrations
    • Providers
    • Hooks
  • Contributing

The implementing provider section that currently lives under concepts should be moved to the new location. The implementing hooks section should be moved to the new location and expanded.

[toddbaert]

Ya, this seems like an improvement compared with what we already have which mixes conceptual and practical dev docs.