Moved puzzle answer from config to database

[aletya]

Resolves #229

[Timothy-Gonzalez]

Looks good, glad we're moving answers to the database. A few things:

• Should remove the config variables so the env variables aren't rquired anymore from both src/common/config.ts and .test.env
• We should have tests for this service - it's not a huge service so this shouldn't be an issue, just want to make sure we are sure this won't break runes & riddles
• Finally, we should have a Staff only endpoint to update these answers without having to connect to the db, but that can come later

[Timothy-Gonzalez]

Good overall, just need to clean up the tests a bit. A few overall things:

• Don't hardcode strings, define them once and if they're already defined use it from before
• Use beforeEach if you're going to do something for each test
• Don't compare errors by message - compare by error (NotFound instead of Couldn't find user!. That way we can change messages without breaking tests. error will always be consistent.
• Look at the coverage to see what is missed. According to coverage: 103-104,116-117,121-122,145-146 are all missed lines. 103-104 and 145-146 don't need to be tested, but 116-117 and 121-122 (puzzle not yet created and if puzzle is already completed) should be tested

This is very nit picky, yes, but I want the foundation of these tests to be good so that someone who extends them extends good code. Once the main tests are done, adding a few tests becomes much easier.