Add a jdbc adapter that uses PostgreSQL with a column store extension

[schoenja]

The is an extension for PostgreSQL called cstore_fdw, which allows PostgreSQL to behave somewhat like a column store instead of a row store, while still using SQL as the query language.

Implementing a store adapter that uses this extension might be a faster way to have a column store in Polypheny-DB than to implement a "real" column store that doesn't already have a jdbc adapter.

Drawbacks

Directly from the official documentation:

Note. We currently don't support updating table using DELETE, and UPDATE commands. We also don't support single row inserts.