Human JWT Auth: Human user of substrate can authenticate to ate-api-server with a JWT issued by an external IDP

[ahmedtd]

We'll probably start with the Google IDP --- once this task is done, a human user should be able to authenticate to ate-api-server using the JWT printed by gcloud auth print-identity-token.

Follow up tasks will need to make JWT auth more configurable, following the example of Kubernetes' pluggable JWT authentication

[EItanya]

Hey Taahir Ahmed (@ahmedtd) and Shruti Nair (@SHRUTI6991), I didn't catch the assignment and put together a version of this today. I'll put up a draft PR tomorrow and we can decide if we want to use it.

One thing I'll say is that I made it a bit more flexible than "just google", it didn't seem like there was any reason to focus too much when a slightly more generic version was also pretty simple.

[SHRUTI6991]

Hi Eitan Yarmush (@EItanya) , I was working on making it generic to use a chain of authenticators. How far are you into the PR? I have a draft ready for it too (almost).

[EItanya]

Hey Shruti Nair (@SHRUTI6991), sorry I logged off and then was very busy this AM. Here's a draft PR if we want to work through that #757.

There are some details I'm not sold on for this PR. First off right now the only k8s JWT auth endpoint is MintJWT, but it doesn't seem like there are any internal callers right now so we may be able to get rid of some of that code