Implement Smarter and Easier System for modders to implement custom collectables

[jasminegamedev]

Please confirm the following

• I have searched to ensure that my feature request is not a duplicate
• My feature request will benefit the general community (i.e. it is not better off as a standalone mod)

Describe your feature

Currently, the only collectable in the game (strawberries) is very hard coded, and many of it's features such as persistence and UI displays are not easily reusable. We should make a system that allows modders to more easily create custom collectibles in their mods, including persistence and UI support. Possibly as some sort of abstract class they can extend, or maybe even something they can define through JSON files, if we want to make it easier to create without needing code.

It might also be nice to add some gamemod events that trigger when a collectible is collected.

Why should we implement this?

This would allow modders to more easily implement custom collectables into levels, without having to reinvent the wheel every time.

Optional

• I will open (or have already opened) a pull request that implements this feature.