Add little area challenges when getting a new power-up

[FelixEder]

For the power ups not guarded by a boss, add some sort of challenge before it. This could either be a hard platforming section, a mini-boss/hard enemy encounter or a small puzzle section.

The point is to make the player work for the reward in order to make it all the more sweet when they get it. Bonus points if the challenges somehow relate to the area they are in (i. e. in the cave maybe the challenge has something to do with caves! 😃)

Power up locations to add:

• [x] Stomp
• [x] Smallfry
• [x] Laser
• [x] Walljump

[FelixEder]

The wall jump challenger area is pretty much done, the wall jump mechanic will need to improve before the area is completely done.

[FelixEder]

Wall jump-mechanic implemented, so wall jump challenge area is complete.

[FelixEder]

The last area, the laser challenge area is now completed in commit a0fb6e8499a6ba653f538663b9c0eac89f84481b, so this issue can be closed.