Implemented a remount command for remounting a backend with a different filename
and restructured the mount command to share a common code base
Implemented the mount resolver option
The umount command now also accepts a mountpath as argument
Fixed a wrong string search in umount
Merge branch 'mount-improvements'

https://github.com/ElektraInitiative/libelektra/pull/46

A new remount command and improvements to the mount and umount command
umount now allows to use path
resolver can be added for mounting