i3 now uses mod4[+shift]+g to increase/decrease inner gaps and +b to do
the same for outer gaps.
The mode name for media has been put into a variable to make potential
dynamic namings possible and avoid duplication.
Having a general script folder makes little sense if the scripts are
targeted to specific applications. This commit moved every script that
solely, or mainly (like ueberzug), targets a single application into
that respective stow module.
