PARKOUR game type
With this release the ` PARKOUR` game type or mode is now functional and distinct from the ` RACE` game type.
Unlike the other game types, parkour games do not involve direct PvP competition.

• A game configured with `game_type: PARKOUR` now runs continuously and players can join at any time. There is no need to queue for a group to form. Players can join while others are already playing.
• Players cannot boost other players in a parkour game.

A ` join_parkour` button is introduced for the in-game GUI. Games with ` game_type: PARKOUR` will use this GUI button. This allows the text in ` lore:` to suit a parkour game. Other game types will use the existing ` join` button.

Arena6 on my pmme.apexmc.co demo server is running the parkour game type.

Currently I am working on recording time-to-win for parkour games to record players' best time, last run time and average time. This will be in a future update.

Other changes:

• Fixed game automatically starting if `min_players:` is set to 0, which is not really a valid setting anyway.
• Configuration loading was not using the defaults provided in the resource files included in the JAR and instead was using hard-coded defaults. This makes no difference to you currently since the hard-coded values matched the included resource files.