Plan Quests

Requested by a few of the more DnD-focused users.

> It would be great to be able to "create" a new quest, including links to who the questgiver is, if there is an item as a reward, locations they need to go to, etc.

>Quests. This would be a great feature to help with building game campaigns and stories. Like other features, it could connect directly to locations, characters, and items. You could describe the type of mission, its start (and end) location, the quest-giver (character), and anything else about it.

It'd be nice if we could figure out a way to make this generic enough to work with campaigns _and_ writing (like rolling it into Plots or something). Just making this issue so we can think about implementation.

This issue is an initial planning request and names no implementation files, tests, or entry points. First review how locations, characters, items, and plots are currently represented, then define the quest scope and acceptance criteria before implementation can begin.

Written by the indexing model from the issue text.