MySQL driver type not automatically detected

As soon as we try to use a database connection where we have a driver for MySQL 8, Hop always try to connect to MySQL by using the old MySQ JDBC driver org.gjt.mm.mysql.Driver and not the new driver com.mysql.jdbc.Driver. That's primary because there isn't any default in the Select database type dropdown

Let's fix this by assigning a default if the user doesnot select anything by trying to recognize the driver just deployed.

Moreover a bit of documentation improvement is needed to clearly state this detail