The function `die` was redundantly implemented in various files.
Move the function into .local/bin/helpers.sh and source that where
previously implemented.
Also prepend the program's name to the message and always terminate the
message with a newline. The newline was previously needed for a small
but unnecessary hack that prevented the need of the `[ -z "$1" ]` test.
In the rare case that no remote url containing `druckdev/dotfiles`
exists, this should still (try to) work.
This could be the case if I rename my username or the repo or in the
even rarer case that somebody forks this... Quite ambitious.
