Extension links are not added to the landing page or collections

[jamesfisher-geo]

For example, the /queryables route is not included in the landing page like it is in the stac-fastapi landing_page method. The code would need to be duplicated in sfeos here

The /queryables route is also not generated as a link for Collections.

Steps to reproduce the behavior:

1. docker compose up
2. http://localhost:8082/ or http://localhost:8080/

Expected behavior
The appropriate routes for a given extension to be advertised in the landing page and collections.

[jamesfisher-geo]

Added with #267.