Add support for generic objects about corectl

[peol]

Not sure I agree with it being connected to the reload command, I'd prefer to keep these separate otherwise we might end up with one command and 50 arguments to it instead of delivering entry commands that does what the naming suggests.

Having a command and an argument (objects and --objects) might be confusing.

Also, it would be nice if the syntax was glob-based which is a de-facto standard nowadays (i.e. corectl --objects="/path/to/objects/*.json", corectl --objects="/path1/genericobject*.json,/path2/genericobject*.json), there should be go libs to support this expansion.