Enable the `DefaultTypeConverter` using an SQLAlchemy DBURI connection parameter

[amotl]

About

Think about an option to enable the DefaultTypeConverter using an SQLAlchemy DBURI connection parameter.

Rationale

In certain scenarios, like when connecting Apache Superset with CrateDB, the implementer is not able to touch any code at all, so she will not be able to configure individual driver options by code. This is in order to close the loop with where @Aymaru originally was coming from, crate/crate-python#395 and crate/crate-python#437, and the actual patches crate/crate-python#442 and crate/crate-python#445.