Add cache support to the LVMLogicalVolumeDevice class
Add cache support to the LVMLogicalVolumeDevice class

This way LVMLogicalVolumeDevice can report whether they are cached, provide
information related to their cache and attach cache pool to themselves so that
they become cached.

vojtechtrefny/blivet,rvykydal/blivet,vojtechtrefny/blivet,vpodzime/blivet,jkonecny12/blivet,vpodzime/blivet,jkonecny12/blivet,AdamWill/blivet,rvykydal/blivet,AdamWill/blivet,rhinstaller/blivet,rhinstaller/blivet