refactor(auth): minimal conversion of db/index to ts

[bbangert]

Because:

• We'd like more code to use TypeScript.

This commit:

• Minimally converts auth-server db/index to TS.

Checklist

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• My commit is GPG signed.
• If applicable, I have modified or added tests which pass locally.
• I have added necessary documentation (if appropriate).
• I have verified that my changes render correctly in RTL (if appropriate).

[dschom]

I dug up the type for most of the any types, cause why not. Take them or leaving depending on how much of a hassle it is. It'd be great to get these in line types defined and reusable at some point.