Script to source muttrc configuration is preferred as it can choose what
files must exist and not throw extraneous error messages on optional
files. Adding the example configuration files to slim out the readme
from the qusal project, also helps with copying the file from inside
the qube itself instead of having to copy inter-qube.
The option push.default=upstream is not suitable for when the branch is
not created yet as it will default to the upstream branch. Even if
specifying the refspec as an argument, it will still push to the default
one, creating a mess.
