MySQL Plugin: create and link my.cnf to allow configuring MySQL

[clessg]

Summary

Adds a $MYSQL_CONF env var to the MySQL Plugin to allow a custom my.cnf (MySQL config file). MySQL does not provide an environment variable, command line flag, or anything else to change the location (it's always computed as $MYSQL_HOME/my.cnf), so we simply create a symlink there pointing to the user's config.

How was it tested?

• Forked devbox, made changes to the mysql plugin, and ensured everything worked in a custom project.

[Lagoja]

Thanks, this is an awesome addition!

I added a similar feature for MariaDB, and also tweaked the detection logic for MySQL vs. MariaDB

[clessg]

Hey John, thank you, looks perfect to me!