feat: add button icon customisability

[iSophes]

Hey there,

Added icon customisability as said in DMs, I've had to do some reworking of the button due to the implementation, however it should still work just as good.

Additions:

• New way of editing icons in buttons with IconProperties table
• Old way of contents are still usable for backwards compatibility, however if an image in IconProperties is provided then that will take priority.

Changes:

• Changed from aftman to rokit as was on the to-do list
• Styled some (not all) files with stylua, maybe could be done if wanted.
• Version bump to 1.2.2,
• Updated tests to include button icon tests