Improve config docs and add references in the dbt docs site

Two docs improvements:
- Make it easier to digest the configs available inside `profiles.yml`: Separate configs by type and include reference examples for local and cloud deployments.
- in dbt docs site, add links back to the complete details of each of the available materializations.

Start by locating the profiles.yml configuration documentation and the materialization pages in the dbt docs site. Separate the profiles.yml configs by type with local and cloud reference examples, and add links from each materialization entry to its complete details. Done means both documentation areas are easier to navigate and the new references resolve correctly.

Written by the indexing model from the issue text.