Is your feature request related to a problem? Please describe.

There is currently no way for yadm to use configuration options passed via git's -c option. This would allow for temporarily changing certain options such as local.hostname, which would be useful for running yadm inside a chroot.

Describe the solution you'd like

Support git's -c option by allowing any configuration option to be passed to yadm (e.g. yadm -c local.hostname=different-hostname -c yadm.auto-alt=false bootstrap).