Dev/ananya/point shop rework

[ananyaanand4]

point shop rework

[Timothy-Gonzalez]

This is a large review - please make sure you don't miss some of the more important comments buried in it since GitHub likes to hide the middle ones. I've summarized below, but make sure you resolve each comment as you fix them. Thanks!

^ Make sure to expand ^

Please make sure you're not deleting existing endpoints - all of the /shop/item endpoints are gone. That's also why the diff is so bad - you're replacing the item endpoints. Instead, just add your new ones.

Two main issues:

• We need to verify the order is still valid every time it is gotten - as quanities change over time. If the quantities in the shop aren't matching anymore, decrease the items they have. So, if they have 15 item1 in their cart, and the quantity of item1 has dropped to 10, they now have 10 item1 in their cart.
• To do so, we should be using singular operations. Calling findOne in a loop is almost always incorrect. Call find with a set of ids you want, then loop over the result. You should also do this for updates. This will reduce the db calls for a large order substantionally, improve latency, and reduce race conditions.

Finally, there's also a bit of minor code convention stuff which should be pretty easy to cleanup.

Feel free to message me if you have specific questions.