Add Town & Dark Gym to Lake of Rage

[vulcandth]

We will be adding a new town in the Lake of Rage with a new Dark-Type Gym. Initial Thoughts and Notes on this:

• There were originally plans to add a town in the Lake of Rage, and there is some info on it from leaked recently.
• In order to avoid adding a "17-th" gym badge, Perhaps this Gym will be an "unofficial" gym. Perhaps they are accepting battles, but have not been fully recognized by the Pokemon league yet. There should be an alternative reward for beating the gym than a badge.
• This town should not feel too out of place from the rest of the game and story.