Time to deprecate AQL?

[Michael Carey]

As AsterixDB evolves, and additional features are added - e.g., DISTINCT 
aggregate support, or properly implemented query-bodied functions, 
supporting two query languages is hugely expensive:  Updating two 
grammars, parsers, rules, tests, ... IMO it is time to let go of AQL as 
an externally supported interface to AsterixDB and only have SQL++ going 
forward.  I think "everyone" has migrated - and if not we should force 
that migration.  (Cloudberry is on SQL++ nowadays, BAD is on SQL++ 
nowadays, ...)  Any objections?  If not, I think we should make this 
decision officially and stop putting energy into carrying the AQL legacy 
around with us.  Thoughts?