Tweaked LDAP TLS Implementation

Tweaked LDAP TLS Implementation

- Moved the ldap function out to our separate service for easier
  testing.
- Added testing for the option.
- Moved tls_insecure part back up above connection start as found more
  reliable there.

Done a lot of real-connection testing during this review.
Used wireshare to ensure TLS connection does take place.
Found LDAP_TLS_INSECURE=false can action unreliably, restarting php-fpm
helped.
Tested both trusted and untrusted certificates.