-smaller environmental adjustments

Added:
-environment
-added a 19th hole

pretty much done for now ^^

-Extended Hole 12's platforms by one more platform

-Reworked 70% of Hole 18 because of multiple fails and problems at the middle part
-> Problems: People got stuck at the boosts because of not enough boost strength; People got launched of the platforms in the curves; People keep roling back

-> Solutions: Changed the Booster strength parts/removed the boosters at different points; deleted the middle part and added some platforms; reworked the booster system of the whole by adding some with lower strength and closer to each other

-All holes have been created and added now

Added hole 5

Updated hole 4: Right hole was missing