Support Kerberos authentication

[dkutalek]

Our Trac instance uses Kerberos authentication and without its support, Cartman is unfortunately unusable for. Please can you implement Kerberos auth for Cartman?

[tamentis]

I believe this should be doable using the https://github.com/requests/requests-kerberos authentication handler, however I don't have a way to test that myself. I would like to avoid adding a kerberos dependency to cartman so I'm guessing setting auth_type to kerberos is what would tentatively import the module.

[tamentis]

@dkutalek is your Trac system public and would you be open to provide me with an account for testing purpose?

[dkutalek]

Thank you for quick response. Unfortunately our Trac is not public. I can try to make a patch as time allows. Other possibility would be to prepare virtual appliance with kerberized Trac, but that is probably overhead.