[Feature Request] Add menu option for loading external (3rd party) texture packs

[EvilSupahFly]

Feature Request

Amulet already supports third party texture packs, but users currently have to add them to the appropriate folder manually, if they want to use any.

Having a menu option with an "Open File" dialog box, which then copies the selected texture pack (preferably in .zip form for simplicity), then loads it and refreshes the 3D Editor using the new pack would certainly add to Amulet's already rich feature list, making it even more attractive as a utility.

Plus, it might resolve this MF'ing texture issue I'm having with Flatpak. 😅😜