[Config] Add initial implementation of the configuration subsystem

[Config] Add initial implementation of the configuration subsystem

This is my initial attempt at a configuration subsystem. I used what
I believe to be sensible defaults for now. They will probably have to
be changed later.

This version of the config system is missing the ability to actually
load a GKeyFile. It just ignores it for now.

This version of the config system is missing versioning and migration
capabilities. They will be added later.