Adding a Piranha Plant

[hunghvu]

Implement all the interaction and turtle shell features of a Piranha Plant. Here is some information based on Mario Wiki.

1. The Piranha Plants inhabit pipes and attack by biting Mario or Luigi if they come into contact with these carnivorous plants.
2. Piranha Plants will not emerge from their pipe if Mario or Luigi are adjacent to or standing directly on top of it, similar to a Bill Blaster.
3. Piranha Plants can be defeated by:
   • Shooting them with a fireball
   • Kicking a Koopa Troopa or Buzzy Beetle shell at them
   • Touching them while empowered by a Starman

Update (Mar. 1, 2021): No. 1, 2 and partially 3 are completed. This issue is keep opened due to in completed tasks.

[dlbjames]

I have just completed Mario getting hit by the plant and removing the plant when it collides with a fireball. However, I would prefer to not do the last 2 bullet points at the moment as part of that implementation is assigned to other team members. Furthermore, it would be even harder for me to build around states / entities that are not even in the game yet.

With that being said, I have tried to add the logic to defeat the plant when Mario has the star man power but can not test this currently. Let me know, if there is anything else I have missed or still need to implement.

The pr for my changes should be coming soon.

Thank you for your time ^_^.