Port Items To `bones_ecs`

[zicklag]

With #541 merged, we now have to migrate the items from before the merge to bones_ecs.

We need to take the items from here in the old commit in Jumpy to their new home here in jumpy_core.

Give a shout out if you want to work on one of these, and I'm often available on chat to help with any questions:

• grenade [Merged by Bors] - feat: port grenade item to jumpy_core. #565
• kick_bomb [Merged by Bors] - feat: add kick_bomb to jumpy core. #568
• mine [Merged by Bors] - feat: port mine item to jumpy core. #617
• stomp boots [Merged by Bors] - feat: reimplement stomp boots #595
• crab [Merged by Bors] - feat: migrate crab to jumpy core. #567
• crate [Merged by Bors] - feat: re-implement and juice crate. #607 (comment)

[zicklag]

I'll start on grenades next.

[HexSleeves]

I’ll take the crab.

[HexSleeves]

Picking up kick bomb

[legendiguess]

I gonna reimplmenet stomp boots 👢

[erlend-sh]

Recent docs (url will probably change soon):
https://fishfolk.org/games/jumpy/developers/creating-items-and-elements/
https://fishfolk.org/bones/overview/introduction/
https://fishfolk.org/bones/ecs_tutorial/the-basics/
https://fishfolk.github.io/bones/rustdoc/bones_lib/index.html

[ThousandthStar]

I think I can do the crate.