docs: wording overhaul, improve Caddy info, update music importing

So, if I see the options correctly, 1.0 removed the ability to do a copy-import? The docs said in-place is default from 1.0, we are beyond that now and the import_files command does not seem to have an argument to do a copy-import.

Edit: I checked it, apparently in-place is not the default even in v1.1.4. What the heck?