Remove advanced LDAP config options from template

These are advanced configuration options that 99% of users don't need. We see an increasing number of support issues because users have set these unnecessarily. Removing the configuration allows things to work fine. There are very few cases where these things are needed and we have tested to ensure the configuration does work when configured properly.

We have each of these options documented in https://docs.gitlab.com/ee/administration/auth/ldap.html so they're available when needed. Removing them from the template ensures we don't have cases where users see the 'knob' and have to 'turn it' simply because it's in front of them.