Add checks that input SQL queries are supported using Grammar in EBNF

If there is some tool that can check that some input (SQL queries) matches the grammar it will be cool feature for the SCC.

Workflow:
- User runs the SCC and pass as agrument path to the SQL queries;
- SCC at first checks that all of the queries are supported and can be converted;
- if any errors -> report about it;
- otherwise -> translation will start.