Remove legacy non-blueapi code

When hyperion is finally fully migrated to blueapi, we will be able to remove the following code:

* Support for legacy GDA mode aka `GDARunner`, launcher shell scripts support for the same
* Support for the InProcessRunner, launcher code for the same
* hard-coded utility functions for loading i03 beamline and plans, since this is all now done via configuration
* Legacy REST API server code aka `create_app`
* Plan registry
* Legacy logging configuration
* Any other things we can think of

We can also tidy up the legacy composite factory methods since these are now all invoked by blueapi

## Acceptance Criteria
- All the legacy cruft is *GONE*