UserDefined DM Grouping

Computed DMs can be added as a "Group" DM by clicking on the "Group" checkbox on the Add/Edit DM popup screen. If the DM is added as a group DM, existing DMs can be added as children to the DM.

When deleting a Group DM or making a Group DM to non-Group containing children, all children will be moved to the end of the TLV.