"Duplex" mode

[Yshayy]

Based on @AvivRubys's idea, we can extend airbag to work as a forward proxy that does authentication.
Client pod can use http_proxy env variable to route external traffic using airbag.
Airbag will do an authentication (should be cached) against OIDC provider (using secrets) and forward the request.
@AvivRubys, @itaym2, @omerlh - what do you think?

[AvivRubys]

I like the idea, the only thing I'm not sure of is wether that should this be a part of airbag or a different sidecar entirely
I wouldn't wanna end up with a "catch-all" sidecar

[omerlh]

I agree with @AvivRubys - I think this should be a separate sidecar.