Create numtracker-friendly internal parameter models

When using Bluesky with BlueAPI + numtracker, there are a few parameters which are baked into our common components which we will now be getting from other places:
- `visit`: BlueAPI will add this to the run engine metadata as "instrument_session", so we can access this within callbacks rather than as a separate parameter
- `storage_directory`: `StandardDetector` is given a PathProvider which uses numtracker, so this directory is calculated for us