Cleanup TaskList View

[munen]

We just merged the biggest [PR](https://github.com/200ok-ch/organice/pull/154 in) organice history.

✋ 🙌 🚀 🎉 and definitively 🎊 (^_^)/

Amazing job, @schoettl

Here's a list of consecutive todos based on that PR. None of them were close to being a blocker for merging, of course:

• [x] Go through the last code review from Jakob
• [ ] Move the discussion with alphapapa into an issue
• [ ] Debounce search input (on big files it can be quite slow otherwise)
• [x] Fix bug: on iOS (scrolling a long doesn't TaskList does not work)
• [ ] Discuss strategy on Search and TaskLists
• [ ] Refactor TastListView and TaskListModal
  • [x] Make them Functional Components
  • [ ] Refactor Leftover Agenda Markup
• [ ] Refactor OrgFile.extractAllOrgTags out of the component
  • This can be done more efficiently in the Reducer
• [x] Write documentation in sample.org
  • Maybe take docs from https://github.com/200ok-ch/organice/issues/141
• [x] Document
  • TaskList with search
  • UX change: Plus for capture
  • Routing for Settings and Sample
  • Routing for Agenda and TaskList

[schoettl]

You too, @munen, thanks for the very good collaboration :)

[schoettl]

Let's use PR #181, we can both edit the description and check the todos as done there.