Use dedicated annotations for quests

[wtimme]

User Story

As a mapper focussing on the quests, I want the quests to appear as dedicated annotations instead of a "glow" on the editor layer, so that I can more easily identify them

This stems from a suggestion by @tordans in #29.

Acceptance Criterias

• Objects that match active quest(s) do not have the blue border anymore
• Instead, at the object's center, a dedicated annotation is displayed
• The annotation is visible even when the editor layer is not visible anymore
• The annotation is shown on top of the editor layer, so that other elements are hidden behind it
• When tapping the annotation, the existing quest interface is displayed

Unhappy Cases

• Mappers might want to access/edit objects that are hidden behind the annotations, but are blocked from doing so
• Too many annotations visible at the same time might clutter the map, making it difficult to navigate
• Too many annotations visible at the same time might have a negative impact on the performance of the app

[wtimme]

With #58, I've added PDF assets for all existing static quests. They can be found in the "Quests" asset catalog.