Support REGEXP_REPLACE #9079
Description
Most SQL databases support REGEXP_REPLACE function (Oracle, Postgres, Vertica, MySQL). Pinot instead supports REPLACE, which just looks for exact string matches and replace them with another simple string.
It shouldn't be very difficult to support this operation in Pinot. Current implementation of ltrim and rtrim already uses Java regex. The main difference is that, for performance reasons, the pattern should be stored somewhere in the AST to be compiled only once.