Make the contract Upgradeable

[5p0rt5BEArD]

The Loot lore will evolve over the years. If this is to be deployed as a corner stone for other contracts to build on, we should make it upgradeable to add future discoveries.

Do we use ERC1976 or EIP2535

[anders-torbjornsen]

EIP2535 gives is a little more complicated, but gives more room to grow. Given Timshel's intention for this to become the canonical classification contract for loot then I think it'll be worth it. Happy to have a stab at this one