Make annotations clickable

[Treutler]

The annotation legend lists all displayed annotations.
Make annotations clickable to select all precursors with this annotation (just evaluate y position of the click).
Could be equivalent to a search, but where to reset this selection?.

[Treutler]

Consider doingthis in the legends plot as well as in the annotations tab.

[sneumann]

Good idea, especially in the presence of many annotations. Will be considered during ggplotly rewrite