feat: added a few more command substitutions

Also re-did the templating algorithm; should be more performant as the
number of overrides increases

FTBTeam/FTB-Mods-Issues#1311

common/src/main/java/dev/ftb/mods/ftbquests/quest/reward/CommandReward.java

@@ -86,7 +86,7 @@ public void fillConfigGroup(ConfigGroup config) {
 	@Override
 	public void claim(ServerPlayer player, boolean notify) {
 		Map<String, Object> overrides = new HashMap<>();
-//		overrides.put("p", player.getGameProfile().getName());
+		overrides.put("p", player.getGameProfile().getName());
 
 		BlockPos pos = player.blockPosition();
 		overrides.put("x", pos.getX());