This creates a custom logger for the log crate which logs everything to a file (/tmp/starship/session_$STARSHIP_SESSION_KEY.log) and it logs everything above Warn to stderr, but only if the log file does not contain the line that should be logged resulting in an error or warning to be only logged at the first starship invocation after opening the shell.
Previously, all modules would have prefixes, which lead to the first
module having a dangling prefix. This change ensures that the first
few modules would instead have suffixes so that we don't start or
end with a prefix or suffix.
A couple of optimizations are done in this PR. One, we now will check config ahead of time to see if a module is disabled before running any module code. Also, we won't try to discover a git repository unless the module requests access to it.
