Add group count capability and improve performance

- implement group count feature in group summary uri
- improve performance for the uri
-- starting from data table makes SUMMARY_COUNT
   SUMMARY_WITH_PHONES quite slow
- add unit test for group summary uri

Must be after Ibc604770cb61ca9fd92280e58f1cd1bbf30c216a

Bug: 5039532
Change-Id: I58fb1040d9025af2e0820a6de85a4eaf2ae30852
3 files changed