Overview of all annotations

[lars-reimann]

Is your feature request related to a problem? Please describe.

Currently the only way to see all annotations is to look at the exported JSON file.

Describe the solution you'd like

• A view in the tool that shows all annotations.
• Option to group by annotation type or declaration type
• Filters (can also feed from the existing filter in the menu bar)

[lars-reimann]

Could be integrated into #495. The annotation counts could be expanded to show all annotated API elements.

[lars-reimann]

No longer provides much benefit once #495 is implemented. Very similar functionality is possible with filters and the next/previous declaration buttons.