feat: Inventory Brick and Model groups

[EmosewaMC]

Implements the brick and model grouping feature in the backpack.

Tested that adding groups, adding lots to said groups, removing lots from groups, renaming groups and removing groups all function as expected and re-logging saves the grouping to the database as well as having the client load the data in the format it expects.
Tested that fuzzing data from the client does not result in bugged or out of sync bags.