This adds a new 'Folders' screen which shows you all your folders and
lets you manage the notes inside them. It currently doesn't allow you to
add or remove Folders, though.
This nearly addresses #18
I'm add a different interface for viewing Notes, similar to card viewer,
and it'll be nice to have a distinction between Journal viewing and Note
Viewing. The biggest difference is that when viewing a Journal, there is
a timeline and you want to be able to easily move between Journal
entries. Whereas with notes, they aren't connected in any obvious way.
It seems that in dark mode the text is not visible as the primary color
remains white. This is a bug in flutter.
https://github.com/flutter/flutter/issues/32180
Thanks to William Lim for reporting.
The flutter default Snackbars are a major PITA to use as they require a
Scaffold, additionaly, they will not be shown if the parent Scaffold is
destroyed, which is the case when deleting a note and returning to the
main screen.
For now I've mostly tried to follow the same style guide as the flutter
repository, with many options disabled. Eventually, maybe it would make
sense to be far stricter.
This simplifies the code quite a bit, at the cost of using this
strange flutter magic of an 'InheritedWidget'.
It basically make a class a global variable.
