backend - workout.js error logging

[iamgeeyuh]

for each route:

• pass an error for the dev
• send an error to frontend to be displayed on error page
  • include an error code understandable to user, and a message to be displayed
  • for example, code: 500, message: Internal server error could be used when some logic in the backend breaks and its not the user's fault
• note that i overwrote a lot of mongoose errors to something that is usable by viewer, but not by us. for example if mongoose passed an error about a table not existing, i would instead send an error code: 500, message: Internal server error to the api that uses the mongoose query. this is useful for viewer, but not for dev
• check every middleware, model, function etc etc being called by these apis for errors

[WilliamLi10]

I think backend errors should stay in the backend. If we need more descriptive error logging, I can just add additional error logging on the backend to stderr or something