Add program_name connectionAttribute for MySQL (#18707)

* Add program_name connectionAttribute for MySQL

Set the program_name connection attribute when creating a MySQL connection, to the same value that we do for other drivers - `config/mb-version-and-process-identifier`

Updating tests

Add test for mysql to ensure `:connectionAttributes` aren't emitted when they are given in `additional-options`

Set `:connectionAttributes` directly in the `jdbc-spec` map (which in turn becomes a property for the JDBC connection) instead of putting in `additional-options`

Fixing some bugs in `additional-options->map`

Relevant links:

* https://dev.mysql.com/doc/refman/8.0/en/performance-schema-connection-attribute-tables.html#performance-schema-connection-attributes-available
* https://mariadb.com/kb/en/performance-schema-session_connect_attrs-table/
* http://mysqlblog.fivefarmers.com/2013/03/26/connection-attributes-in-mysql-5-6/