Remove mariadb as a dependency of pfconfig

[jrouzierinverse]

Is your feature request related to a problem? Please describe.
Remove mariadb as a dependency of pfconfig

Describe the solution you'd like
When upgrading, there now seems to be a chicken-and-egg scenario between starting pfconfig and MariaDB.
Causing issues upgrading PacketFence

[satkunas]

@lzammit @fdurand please add more detailed information