protocol: add Objects field in SearchRequest
that will allow us to search for a sequence.

Our current goal is to be able to search a sequence
of specific nodes based on their context id in order
to get their UUID.
populate an access table in DND with every known node in the DSD
database. Lookup the access table on every node connection to make
sure it has not been revoked.
dsd: add delRequest handler function
code cleanup
Merge branch 'fetch_node_uuid'