Implement DML for file datastore
DML for file datastore with unit testcases
Fix for MB-12513
CREATE PRIMARY INDEX ... USING LSM

primary index can be created using VIEW or LSM, by default VIEW will be used
if USING token is not specified.
Fix for MB-12533
Fix for MB-9360 and MB-12248
Meta() should return all meta-data associated with a key
fixed decoding of meta flags
MB-12505. Allow dropping of primary index
Support dropping of primary indexes using grammer
drop primary index on keyspace_ref
Remove redundant variable from dropIndex struct
Update design_links.md
Integrated with cbq-bridge.

cbq-bridge is the admin interface to 2i, can be used to,
- publish CREATE INDEX and DROP INDEX stmts to 2i
- load list of indexes available from 2i

Note:
  Yet to figure out how to get back the topology information for each
  index and get notified when topology changes or when a new index
  is added.