[build.webkit.org] Remove old dead code related to authentication. We now have 'Login with Github' functionality. We don't need this old custom code. Anyways this is dead code since we upgraded from buildbot 0.8 to newer version.
Pull request: https://github.com/WebKit/WebKit/pull/14965
Committed 265161@main (231cc6abf642): <https://commits.webkit.org/265161@main> Reviewed commits have been landed. Closing PR #14965 and removing active labels.
<rdar://problem/110792442>