Improve LDAP error messages
Debugging LDAP problems is currently very difficult because error messages are not specific enough.
Steps to reproduce
An example can be appreciated by configuring LDAP through
gitlab.rb with a wrong password and compare this with the error given by configuring it correctly but having the AD user blocked.
Other examples can be seen when using invalid email addresses or invalid characters within a username.
I would expect to have enough information to know where my problem is located after checking with
sudo gitlab-rake gitlab:ldap:check
Relevant logs and/or screenshots
(Paste any relevant logs - please use code blocks (```) to format console output, logs, and code as it's very hard to read otherwise.)
Output of checks
After reconfigruing LDAP with a wrong password.:
$ sudo gitlab-rake gitlab:ldap:check Checking LDAP ... LDAP users with access to your GitLab server (only showing the first 100 results) Server: ldapmain Checking LDAP ... Finished