Similarly to the qutebrowser module we change the layout to have a
program name at the top-level and all required files for that specific
program within, whether they reside within .config, .local or anywhere
else.
We use dotter mappings to achieve this.
Papis reload will now only rebuild the cache of the currently
active library by default. To rebuild the cache of all libraries
papis knows, simply supply the `--all` switch.