I24 SSX: Get beam centre from config server

[DominicOram]

To display the crosshair on the oav stream we need to know where it is. The information is currently at /dls_sw/i24/software/gda_versions/var/display.configuration but we should get this information from the config server (https://daq-config.diamond.ac.uk/docs#). To do this we need to:

1. Move the display.configuration file into somewhere in /dls_sw/i24/software/daq_configuration
2. Make sure that GDA is updated with this new location and still works as before
3. Make sure https://github.com/DiamondLightSource/mx-bluesky/blob/23f5af2273f3c54433f5651a9fb8842eee5b4132/src/mx_bluesky/beamlines/i24/serial/parameters/constants.py#L28 is also updated
4. From the UI, call the /config/{file_path} endpoint on the config server to get the information from that file
5. Get the beam centre out of that file and draw a crosshair on the screen