WIP feat: add LDAP invite functionality

[gartnera]

This PR adds functionality to invite via LDAP in addition to the invite string. These changes don't allow login via SSH, only processing the invite. To invite a user via ldap, do the following:

• user invite test
• ssh -P 2222 test@localhost
• input the password
• the ssh key is now associated with the user

Note this PR is a work in progress (WIP). I need to do some more refactoring and testing before being confident in a merge. Feedback would be appreciated.

[gartnera]

Can we add govendor sync in the Makefile?

[moul]

Thank you for this PR, what't the current status?

Can we add govendor sync in the Makefile?

Yes, do not hesitate to add new rules as soon as it's helpful

[moul]

Hi @gartnera, I just switched to go modules

Do not hesitate to ping me if you encounter issues to continue this PR

[RootMePLS]

Any news here?

[Grounz]

Hi,

Any news here?

[moul]

FYI, I would love to see @gartnera finish this PR, but with what I plan to do on the #210, there will be an easier way to support various authentication providers, i.e., by having sshportal calling your own API that can do whatever you want to validate a user