* remove phase one/two distinction and hdbquery typeclass
* move extensions to default-extensions
* switch to LazyTx which only acquires a connection if needed
* move defns from TH module into Ops module
* remove tojson orphan instance for http exception
* remove orphan instance for dmlp1
* getTopLevelNodes will not throw any exceptions
When using self referential relationships in boolean expressions, the exists clause incorrectly uses the table names to qualify columns which will be the same for parent table and the child table. This is now fixed by generating unique aliases as we traverse down the relationships.
Insert trigger function: If query affects no rows then return `null`
Insert trigger function is modified to have
`IF r IS NULL THEN RETURN null; ELSE RETURN r; END IF;` in return statement.
### Description
What component does this PR affect?
- [x] Server
### Related Issue
#494
### Solution and Design
Use `quote_ident()` SQL function over `constraint_name` in insert trigger function definition.
### Type
- [x] Bug fix (non-breaking change which fixes an issue)
* fix primary key changing on upsert, fix#342
* add 'update_columns' in 'on_conflict' object, consider 'allowUpsert'
* 'ConflictCtx' type should respect upsert cases
* validation for not null fields in an object
