Constrain drive schemes to be Rockstor compatible

[phillxnet]

Thanks to forum member m3elloa for highlighting this issue. It is possible to select many drive schemes that are not Rockstor compatible, ie LVM variants with single and multiple drives. This ends up with a broken system as Rockstor's own drive management can't cope with LVM.

The hope is that we can disable such options as LVM from anaconda so that incompatible installs might be avoided.

I have not looked into the practicality of this issue but noting here in case it is viable.