[Feature] Centralize developer docs

### Is this your first time submitting a feature request?

- [X] I have read the [expectations for open source contributors](https://docs.getdbt.com/docs/contributing/oss-expectations)
- [X] I have searched the existing issues, and I could not find an existing issue for this feature
- [X] I am requesting a straightforward extension of existing dbt-adapter functionality, rather than a Big Idea better suited to a discussion

### Describe the feature

We have several sets of docs for each adapter. These point to `dbt-core` in many cases. But the relevant repo should really be `dbt-adapters` now. We want to make this an information hub for third party adapter maintainers. This will help drive consistency across first party adapters as well as drive traffic to this repo. Here's where some existing OSS/Adapter docs currently live:

- https://github.com/dbt-labs/dbt-core/blob/main/CONTRIBUTING.md
- https://docs.getdbt.com/community/resources/oss-expectations
- https://docs.getdbt.com/community/contribute
- https://docs.getdbt.com/community/resources/oss-expectations#youve-opened-a-new-issue-what-can-you-expect-to-happen

### Describe alternatives you've considered

_No response_

### Who will this benefit?

- Third party adapter maintainers
- First party adapter maintainers (hey, that's us!)
- Contributors

### Are you interested in contributing this feature?

_No response_

### Anything else?

_No response_