Reorganise & cleanup

[cyqsimon]

Got rid of a lot of old packaging code.

• I checked all currently tracked downstream packagers, and it seems like no one is actually making use of make. And seeing that there's no one to maintain it, I thought it'd be better to just get rid of it. We can revert if necessary.
• I also got rid of the very outdated static manpage and completion script. I do plan to automatically generate them using clap_mangen and clap_complete in a future PR.

And I created the /res directory to accommodate the incoming logo (see #317) and other related stuff in the future (e.g. desktop entry).

[kpcyrd]

Arch Linux was making use of docs/bandwhich.1. It seems the dependency to clap_mangen has not been added yet, should 0.22.0 ship without a manpage?

[cyqsimon]

Arch Linux was making use of docs/bandwhich.1. It seems the dependency to clap_mangen has not been added yet, should 0.22.0 ship without a manpage?

Dang. Forgot about this. I'll add it and release it as 0.22.2.