GUI: Group targets in device screens

In the edit device screens dialog, target OPIs should be grouped into categories instead of having one long list with everything, to improve ease of use and to be consistent with the changes to the synoptic editor in https://github.com/ISISComputingGroup/IBEX/issues/2579.

Start with the edit device screens dialog and compare its target OPI list with the category changes made for the synoptic editor in issue 2579. Identify how target OPIs are currently presented and where the dialog is implemented. Done means the targets are grouped into categories rather than shown as one long list, while remaining consistent with the synoptic editor.

Scritto dal modello di indicizzazione a partire dal testo della issue.