Support SPNEGO authentication

[Ex0danify]

Hey there,
LOVE using Zen as a browser on my companies work notebook, the grouping and everything makes this just PERFECT.

Since I'm working in a coorporate environment, we use webservices based on IBMs WebSphere for certain internal sites. Those use SPNEGO authentication, which does not seem to to be supported by Zen (but is supported by Firefox.)

This is the error, that gets shown in Zen Browser:

As said before, Firefox works just fine. I don't know anything myself about SPNEGO auth, but it seems to be well documented here:
https://www.ibm.com/docs/en/was-liberty/core?topic=authentication-single-sign-http-requests-using-spnego-web