Add support for MariaDB about spring-data-r2dbc

[schauder]

There is someone working on a MySql driver and my understanding is that MySql and MariaDB are really similar, so it might be easy to adapt that one.

Take a look at https://github.com/mirromutth/r2dbc-mysql

[mp911de]

We're a small team and currently, we cannot afford to start a new driver implementation. We're happy to guide you through the technical bits if you want to start building a MariaDB/MySQL driver.

Spring Data R2DBC will pick up a MySQL/MariaDB dialect as soon as a driver is available.

[krishna81m]

Curious, how big of a difference is for any JDBC compliant library/driver to work ?
Wonder if you can guide us by pointing to core classes that need changing to work with MariaDB?

[dheeraj29]

@schauder @mp911de I am closing this issue in favour of #75 . As per MariaDB, it uses the same wire protocol of mysql itself.
https://mariadb.com/kb/en/library/mariadb-wire-protocol/

So it should be compatible without any issues.

[mp911de]

Done.