knowledge: manager addition

• NEW Adds manager to knowledge with a command to load mappings into an existing knowledge base from a file. E.g. inveniomanage knowledge load kb_name /path/to/file.kb

Reviewed-by: Jiri Kuncar <jiri.kuncar@cern.ch>
Reviewed-by: Guillaume Lastecoueres <guillaume.lastecoueres@techie.com>
Reviewed-by: Leonardo Rossi <leonardo.r@cern.ch>
Signed-off-by: Jan Aage Lavik <jan.age.lavik@cern.ch>