Adding Ubuntu session for SAML authentication

[romulojales]

Modify this link to include the branch name, and possibly the page this PR modifies:

https://osc.github.io/ood-documentation-test/latest/authentication/adfs-with-auth-mellon.html

Add your description here

Adding specific paths, commands and quirks when configuring SAML (mellon) in Ubuntu.

[johrstrom]

I'd merge this quickly, but I just need a minute to pull it down and verify the formatting is OK - I believe the content is fine, but formatting can be tricky. I'm busy juggling a few other things, but I'll get to this shortly.

[johrstrom]

Looks good, thanks!

[johrstrom]

Went to merge this, and see your commits aren't attributed correctly to your github user. I'm OK to merge as is, but I think it's important you get full credit, so if you want to fix the commits you can do so now.

[romulojales]

Went to merge this, and see your commits aren't attributed correctly to your github user. I'm OK to merge as is, but I think it's important you get full credit, so if you want to fix the commits you can do so now.

@johrstrom , thank you for noting that. I've amended the commits with my public profile.

[johrstrom]

Thanks for the contribution!