Lookup, Multi-Lookup and Search API improvements

• Rename MessengerSearchUsers to MessengerSeatchContacts
• Add LookupUD.Params struct
• Add SearchUD.Params struct
• Add MessengerLookupContact function
• Refactor UdMultiLookupCallback.Result
• Add MessengerLookupContacts function

requested review from @brunomunizaf

assigned to @darrarski.xx

enabled an automatic merge when the pipeline for f71d2e2b succeeds

aborted the automatic merge because source branch was updated

added 1 commit

• aac2bf94 - Fix messenger example app

Compare with previous version

enabled an automatic merge when the pipeline for aac2bf94 succeeds

mentioned in commit df7e9900

merged