Support SQL Parser & Transformer for custom tektite sql

[mohnishbasha]

Context

• Users use tektite language to work with Tektite to process data.
• However, SQL is more widely accepted and adopted when it comes to working with data across the industry.
• This is also evident with the popularity of KSQL which is a streaming sql engine to process data in real time from kafka streams.

Issue

• Currently tektite does not readily support SQL.

Proposal

• The proposal here is to implement a sql parser using antlr for custom tektite sql with windows, probably be similar to ksql syntax.
• a transformer to transform it to tektite language.
• This will help users to define streams or queries using SQL as an alternative to tektite language.
• The SQL engine would then internally translate it to tektite lang so everything else could stay the same.