[Meta] Settings window
Description
There are a couple of issues with the current settings window:
- choosing a "default source" for scanner doesn't make much sense with the new design (see #660)
- we should give [Meta] Settings windowclues of what data we collect (see #720 (closed))
- we should warn when expected stuff are missing (see #111)
- visually, the window looks a bit messy
- we need to support plugins
Proposal
As always, feel free to comment, folks!