Co-authored-by: Alex Vasilev <[email protected]>

* feat: Support SET NAMES literal [COLLATE literal]

* feat: Support SET NAMES DEFAULT

* clippy

…561)

* feat: Parse special keywors as functions (current_user, user, etc)

* explain special field

…variants, allow escape char for like/ilike (#569)

* Remove [not]like,[not]ilike from binary operator list

* Add like, ilike and similar as an expr variant. Also adds support for escape char to like/ilike

* Add parsing logic for similar to, update parsing logic for like/ilike

* Add tests for similar to, update tests for like/ilike

* Fix linter warnings

* remove additional copyright license from files

* Add more coverage w/wo escape char for like,ilike,similar to

* Clarify contribution licensing

* less whitespace

* Split trimwhereFlag and trim_char expr to seperate members of Expr::Trim

* update trim parsing logic to handle no flag + char from expr combo

* add tests

* Allow trim flag without trim_what expr

* Add trim flag without trim_what test

Co-authored-by: Alex Vasilev <[email protected]>