Merge branch 'feature/mysql-port' into 'master'

Define MySQL port by its own (rather than in the host with :port)

As the title says, this MR allows defining the MySQL server port in a new variable.

After having done the work I saw that it can simply be passed with the hostname, like `hostname:port`....
so I'm not going to be sad if this MR is getting closed asap. *rofl*

Leaving it here anyway.

See merge request !187