Authentication - Enable Certificate Auth

[daesimps]

We do not allow usage of client secrets, especially those stored in a plain text file. The app should support authenticating using a certificate, which can be specified by subject ID or Thumbprint.

[jasperbaes]

Hey @daesimps , thanks for bringing this up! I'm also a huge fan of using certificates for production over client secrets. I've already spent some time trying to implement this (along with browser login), but haven't had much luck so far. I'll give it another shot soon.