Simple backpack feature.

[ghost]

Is your feature request related to a problem? Please describe.
I would like to have a feature that opens a GUI with items, similar to an Ender Chest, but larger. The GUI should not be tied to physical backpacks but rather be accessed through a command. Just simple backpacks feature

Describe the solution you'd like
The feature should allow players to open a customizable GUI through a command. The size of the GUI should be configurable based on permissions, providing flexibility for different user groups. The configuration should allow advanced settings to adjust the size of the GUI dynamically, depending on the player's permission level.

Additional context
Please ensure the configuration is easily adjustable, and the feature integrates well with existing permissions systems. Example permissions: backpack.size.small, backpack.size.large, etc.

[vLuckyyy]

After duscussions with @Kryspek, I think this feature could be cool.