Clickhouse SQL generation for datatypes.

[grigoryan-sergey]

The SQL generated by the parser does not work inside Clickhouse. The problem is in datatypes, which are case sensitive in Clickhouse. I suggest generating a Clickhouse version for datatypes. This will still work for other databases where datatypes are not case sensitive (like postgres) and will also work for Clickhouse. Interesting enough some datatypes are also not case sensitive in Clickhouse, but the ones which are case sensitive, are converted in the PR.

[iffyio]

Hi @grigoryan-sergey hmm with the current changes I expect a lot of tests to fail since we''ve also changed types that affect other dialects. I wonder if there's a way to support both styles 🤔 (I guess first would be if Clickhouse is the only supported dialect with a different behavior)