More precise control of sequence & alignment associated annotation row visibility

Since introduction of per-chain structure derived annotation tracks (2.11.2), it is now common for sequences to have several secondary structure tracks:

- PDB structures
- AlphaFold models
- JPred secondary structure prediction
etc...

We now need the ability to show a specific instance of these annotations, or 'hide all but this instance'.

Even better, a pop-up browser that shows all annotations available, their relationship to the sequence (Jpred, AF-id, PDB-id, etc..) and whether they are visibile or added to the alignment. Suggest the latter be considered a separate issue.