Create SQL/NoSQL lexers and parsers

[mostafa]

The idea is to remove reliance on CGO, so that plugins can compile and run on any platform supported by GatewayD, like Windows. Since we only need lexical analysis and parsing to get the CST, ANTLR and similar projects can help create those lexers and parsers fairly quickly.

• PostgreSQL lexer and parser #16
• MySQL lexer and parser
• MSSQL lexer and parser
• SQLite lexer and parser