feat: support additional SubQuery children for any relational operator, interpret SubQuery with single output as expression

Co-authored-by: Georgy Moshkin <gmoshkin@picodata.io>

Kurdakov Alexander authored 6 months ago and Alexander Kurdakov committed 6 months ago

Previously some public lua functions in core-router.lua failed
returning nil instead of an error. As a result in a case of error
rust code treated it as success, but failed to pop expected results
from lua stack. So, instead of a real error user got lua reading
errors. Fixed.

Co-authored-by: Denis Smirnov <sd@picodata.io>

feat: add logic of correct local SQL generation for the case of asterisk (not in a view of references, but as "*")

fix: remove useless SubQuery nodes, fix logic of vtable columns naming (automatic indexes instead of names from local SQL metadata)