refactor(auth server): typescript lib/oauth/metrics

[jodyheavener]

Closes #4879

Part of a larger effort to adopt TypeScript in the Auth Server.

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I'm trying to take a slow, educational approach to TypeScript, so please feel free to tear this apart.

[chenba]

It actually might be easier just change the config file to .ts, install @types/convict, and export typeof conf in the config ts.

[jodyheavener]

So many implications for changing the config file to typescript 😆

[chenba]

If you add "[skip ci]" to your commit message of a wip commit, CircleCI will skip CI.

[jodyheavener]

@chenba fair, yeah, this config change has just been so far reaching that I'm using CI to find all the spots 😅

[jodyheavener]

@chenba Okay, so we're passing now, but you'll notice I had to up certain timeouts an quite a bit.

I'm guessing it has to do with mocha using TypeScript and needing to compile everything repeatedly. Or perhaps it's the use npx (because it will install ts-node if it is not present), but because we npm i before the test I wouldn't suspect it's that. At any rate, I don't feel great about the timeouts. If you have any thoughts I'm all ears.