Show a hint in the custom UI of what to do next to unlock the next item for every merchant. Note that this will involve refactoring the entire codebase which is really really large.

The idea is the AddItem(...) function takes in an additional param 'bool condition' or 'Condition condition' where condition is the requirement that needs to be met in order for this item to be added.

These conditions will be added to a list in each Shop class in a specific order in terms of progression.

Whenever the custom UI is shown, a condition in the form of a hint as text will be taken from the top of the list and shown in the UI.

Again this will be a lot of work to do so I'm not really willing to do it anytime soon unless someone motivates me.

- Add shops for zoologist, golfer, princess
- Add shops for cat, dog and rabbit pets (and all the slime pets)
- Add shop for bunny, squirrel

- Reduce sell price of Bunny mount from merchant
- Reduce sell price of painter accessories