Jaime - Final Fixes

Today I did a couple of small improvements and bugfixes including:

Added a new script that makes cars move forward and backward from a starting position as a new obstacle.

Fixed the colliders of some obstacles in the third section of the level.

Added the speed boost collectible for y'all speedrunners out there.

Fixed a bug where the player floats after restarting from the second portion of the level.

Changed the player collider.