Extend limit&offset statements

[Lagovas]

Extended parser with postgresql specific statements syntax and refactored rendering from the AST to the string in same format as it was parsed. But wasn't added support of cursor specific syntax for PostgreSQL with FETCH + limit&offset. It is much more complicated and should be implemented together with cursor's support. PostgreSQL's format - https://www.postgresql.org/docs/current/sql-select.html#SQL-LIMIT MySQL's format - https://dev.mysql.com/doc/refman/8.0/en/select.html

Checklist

• [ ] Change is covered by automated tests
• [ ] The coding guidelines are followed
• [ ] Public API has proper documentation in the Acra documentation site or has PR on documentation repository with new changes
• [ ] CHANGELOG.md is updated (in case of notable or breaking changes)
• [ ] CHANGELOG_DEV.md is updated
• [ ] Benchmark results are attached (if applicable)
• are up-to-date (in case of API changes)