Improve UI for planar annotations

[fedorov]

I think planar annotations should be supported in a way similar to SEG/RTSTRUCT. Right now, it is virtually impossible (at least in the IDC fork) to determine if a given series has any planar annotations, or where they are.

• when an SR with a planar annotation is dropped into the viewer, it becomes available in a section labeled "Annotations" or similar in the same place where SEG/SR are located
• when the corresponding image series is available (when annotation is SCOORD), image series can be loaded into the viewer automatically
• when an SR that contains planar annotations is loaded, individual annotations within the SR should show up as a list of items (like segments or structs in SEG/RTSTRUCT), and clicking on the individual item in the list should scroll to the location of that annotation in the series
• it should not be possible to modify an existing planar annotation that was loaded (right now, this is possible)

Note that planar annotations may or may not be accompanied by any measurements, so there should probably be a distinction between annotations and measurements. Also, in IDC fork we don't want to confuse the user by allowing to create measurements/annotations that cannot be saved, but this should not prevent IDC viewer from displaying existing annotations/measurements when available (similar to how we display SEG/RTSTRUCT).

Let's discuss how this fits into OHIF development plans, and what is the effort of doing this, if we agree it makes sense.

[sedghi]

@igoroctaviano what is the status on this? is it still applicable?

[igoroctaviano]

Related to #1215
@rodrigobasilio2022 please revisit this ticket to get information on how we should display measurements in the OHIF measurements panel.