Selectively revert suspect commits causing API instability (#852)

* Revert "Fix related media endpoint (#808)"

This reverts commit d7962f1.

* Selectively revert "Add logging and fix all logging contexts (#790)"

This reverts commit ce33572.

* Revert "Refactor search controller for consistency and clarity (#778)"

Preserves #730

This reverts commit d26df92.

* Fix divergent Elasticsearch configurations

In #712 Elasticsearch configuration was moved out of the search controller area into the Django settings module. This unifies access to ES from across the application and is part of the refactoring being done to support the ES versioned index, multi-stage deployment. This commit keeps those changes and applies them to the old search_controller.py module that did not exist at the time the configuration change was applied.

* Lint

* Prevent circular import

We can replace the Any back with the serializer type in the future.

* Add back related media endpoint integration tests

* Lint

Author: sarayourfriend