Allow for display items to have their name set and shown

[Sven65]

Please describe your feature request

Since the items don't use the item name to figure out that they're Slabbo items, we can set the name to anything, and by such also allow for a custom name to show up with the displayitem.

Describe the solution you'd like

In order to do this, we should first stop setting the name to slabbo item or whatever it's called, and add a command with a permission node to toggle the display flag of the item name.

When the flag is changed, the item might need to be redropped. Check if it does, if not, even better.

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
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