MythZoneMinder: fix the grabbing of the live stream images

* Add a missing field to the ShareData struct added it later ZM versions
* Change the minimum supported ZM version to 1.24.0.
* Remove the v4l2 hack

Note: this bumps the MythZoneMinder protocol version so both the FE plugin
and mythzmserver need to be updated.

Refs #8182
Added new service API call to only get the directories from a certain storage group.

Signed-off-by: Stuart Morgan <smorgan@mythtv.org>
Added new service API calls to rename or delete a certain file.

Signed-off-by: Stuart Morgan <smorgan@mythtv.org>
Updated the DeleteFile and RenameFile service API methods to use storage groups. Added more checks to the RenameFile method.

Signed-off-by: Stuart Morgan <smorgan@mythtv.org>
Change mythbackend --printsched to require a running, master backend.

Previously, using the --printsched option fell back to running a local
scheduler when the master backend couldn't be reached.  That made it
too easy to miss the fact that the master was not running.  Using
--printsched now fails if the master backend can't be reached.  Use
--testsched if running a local scheduler is wanted.