CONTENTdm children need metadata too

[bondjimbond]

Similar to #462 - Compound Objects coming from CONTENTdm are getting very weak metadata, while the parent's rich metadata is invisible due to the Compound Object SP's only displaying child metadata. We need the option to apply the parent metadata to the first child or all children.

[bondjimbond]

Note however that the "migrated from" URI should still be unique to each child.