Add a setting to allow setting the initial voting type.

[Reispfannenfresser]

Description
There should be a server sided setting to set which vote should be the first to be called when voting starts.
This setting should have a unique type that only contains the available vote types.

Motivation
Some people may always want to vote for different gamemodes first. Having to wait for the mapvote to finish first is not desirable in this scenario.
If people want to add different Vote types, these would need to be integrated into the existing system somehow. Being able to set the initial voting type is a good approach to solve this problem.