Adding a custom X509 username field

Review Request #10131 — Created Aug. 28, 2018 and submitted — Latest diff uploaded

Information

Review Board
release-3.0.x
85f19bb...

Reviewers

Adding a custom X509 username field.

This will allow for configurations that use other front-ends for authentication. One example might be mod_auth_mellon for SAML SSO support (which sets MELLON_NAME_ID).

Not sure how to inject settings in test_x509_auth_middleware tests to test "CUSTOM".
Tested on a copy of our reviewboard server which uses mod_auth_mellon and references our SSO server. Works like a charm!