Add ODBC support

[GitMensch]

The README says

Ocesql is currently supports PostgreSQL only

What do you think about adding support for unixODBC, allowing Ocesql to be used with a wide set of DBs?

[n-isaka]

We would like to correspond to multiple DBs as well.
But I have not done it yet.

I would like to implement it in the future.

[GitMensch]

"Update": I see this as a very low priority for myself now as there are enough "general" issues with the parser (limited support for standard COBOL, bad diagnostics, too much things parsed #25, non-standard DECLARE #26 missing EXEC SQL like #66 #65 #92 #33 #89 and others) and also several things in the runtime (both general and PG specific); I'd definitely prioritize all of those higher.

To be clear: it is good that ocesql exists and it is usable with PG for several things - I just don't consider it in a state that allows adding an additional driver "anytime soon".
If someone really needs ODBC then esqlOC exists since quite a long time (what works works well; that is also used in production) and now also GixSQL would be an option (of course the later also has several [other] issues).