* fix nested insert with returning computed fields gives error, fix#3609
* revert using ordered hashmaps, sort columns based on ordinal postion
* fix 1. keys order 2. json/jsonb column value in nested insert returning
* add a note for sorted columns
* cast 'VALUES' expression as table row type
* use single CTE expression for generating returning for nested inserts
- Move MonadBase/MonadBaseControl instances for TxE into pg-client-hs
- Set the -qn2 RTS option by default to limit the parallel GC to 2
threads
- Remove eventlog instrumentation
- Don’t rebuild the schema cache again after running a query that needs
it to be rebuilt, since we do that explicitly now.
- Remove some redundant checks, and relocate a couple others.
* save permissions, relationships and collections in catalog with 'is_system_defined'
* Use common stanzas in the .cabal file
* Refactor migration code into lib instead of exe
* Add new server test suite that exercises migrations
* Make graphql-engine clean succeed even if the schema does not exist
* Separate DB and metadata migrations
* Refactor Migrate.hs to generate list of migrations at compile-time
* Replace ginger with shakespeare to improve performance
* Improve migration log messages
These changes also add a new type, PGColumnType, between PGColInfo and
PGScalarType, and they process PGRawColumnType values into PGColumnType
values during schema cache generation.
