Consider the best structure to make devices searchable

We currently have a structure of:
* One common area for all generic devices
* A section for beamline specific devices

Given we're getting many more devices now this is getting unorganised and hard to find specific things.

## Acceptance Criteria
* There is a discussion on what is the best way to organise the repo for later searching (involve people new to dodal/scientists)
* We document and implement the decision