Fix camera name retrieval
The current code deduces the camera name by splitting the device string
camera_name=evt_bvdata.attr_name.split("/")[-2]
however the camera is initialised using the lima instance name. This means the instance name, and device name have to be consistent for the bpm viewer to find the devices.
Instead we should use a lookup table to get back to the cached device proxy from the tango url of the device