The hooks API had several issues which are summarized in this comment:
https://github.com/openedx/wg-developer-experience/issues/125#issuecomment-1313553526
1. "consts" was a bad name
2. "hooks.filters" and "hooks.Filters" could easily be confused
3. docs made it difficult to understand that plugin developers should use the catalog
To address these issues, we:
1. move "consts.py" to "catalog.py"
2. Remove "hooks.actions", "hooks.filters", "hooks.contexts" from the API.
3. re-organize the docs and give better usage examples in the catalog.
This change is a partial fix for https://github.com/openedx/wg-developer-experience/issues/125
