Remove ProtoBuf as save file serializer

[Jannify]

This pr removes ProtoBuf as a save file serializer while keeping it's functionality for the client and the server resource parser. It also moves some classes in NitroxServer.GameLogic and NitroxServer.Serialization to better reflect their behavior.

Tested in-game with a small base and a seamoth.

[Jannify]

[PropertyDescription("Possible values:", typeof(ServerSerializerMode))]
public ServerSerializerMode SerializerMode { get; set; } = ServerSerializerMode.JSON;

Shouldn't we remove this in Nitrox/NitroxServer/Serialization/Serverconfig.cs?

Normally yes but because Meas said we maybe want to introduce a database format latter down the line I kept all the logic which makes multiple serializers possible

[dartasen]

I'm not sure that's a good idea right now