[Api] Give & Pick Slimefun Item api

[JustAHuman-xD]

Description

Addons with complex SlimefunItem's that can have data different for the same slimefun item often have problems with the middle click & give item command, as they may lack some data that would be there when attained in survival, this PR adds 2 methods to help solve that problem.

Proposed changes

• Added SlimefunItem#getGiveItemResult(Player)
  • Defaults to getItem and is called in GiveCommand in place of getItem
• Added SlimefunItem#getPickBlockResult(Player, Block)
  • Also defaults to getItem and is called in MiddleClickListener in place of getItem
    • Also adds an instanceof to MiddleClickListener as the event returns HumanEntity not Player and I didn't want it to be inconsistent, testing is needed to make sure it still works

Related Issues (if applicable)

N/A

Checklist

• I have fully tested the proposed changes and promise that they will not break everything into chaos.
• I have also tested the proposed changes in combination with various popular addons and can confirm my changes do not break them.
• I have made sure that the proposed changes do not break compatibility across the supported Minecraft versions (1.16.* - 1.20.*).
• I followed the existing code standards and didn't mess up the formatting.
• I did my best to add documentation to any public classes or methods I added.
• I have added Nonnull and Nullable annotations to my methods to indicate their behaviour for null values
• I added sufficient Unit Tests to cover my code.

[github-actions]

Your Pull Request was automatically labelled as: "🔧 API"
Thank you for contributing to this project! ❤️

[github-actions]

Slimefun preview build

A Slimefun preview build is available for testing!
Commit: 8f66bf3

https://preview-builds.walshy.dev/download/Slimefun/4252/8f66bf32

Note: This is not a supported build and is only here for the purposes of testing.
Do not run this on a live server and do not report bugs anywhere but this PR!

[WalshyDev]

I really like this, great job!

I'm not the biggest fan of giveItem since /sf give is a command not just a special mc thingy but, I think it's fine. Generally, I try to make APIs that work first-party the same as they do third-party. So, any addon could do something similar rather than it being a special Slimefun hardcoded thing

For this situation, I think it's fine. I haven't seen others asking for a similar functionality and if someone wants to make one, we can easily move over.

[TheBusyBiscuit]

Also a fan of this, simple but a very useful addition to the API 👍🏻
Thanks!