Remove nslcd and related packages on Debian

This is part of the change to replace nslcd with sssd to
support multiple secure ldap backends.

This change removed nss-pam-ldapd (nslcd, libpam-slapd,
libnss-slapd) on Debian based stx system.

nscd is removed in
https://review.opendev.org/c/starlingx/tools/+/854217

Test Plan on Debian:
PASS: Package build, image build
PASS: System deployment
PASS: Verify nslcd, libpam-slapd, libnss-slapd are not installed.
PASS: ldap functions work properly (ldap user creation, user login
      on console and by ssh etc).

Story: 2009834
Task: 46069
Depends-On: https://review.opendev.org/c/starlingx/metal/+/854203
Signed-off-by: Andy Ning <andy.ning@windriver.com>
Change-Id: I87de211876a00c0b0a0d629dde70e13c0feb3df0

debian_pkg_dirs

@@ -66,7 +66,6 @@ kubernetes/kubernetes-unversioned
 kubernetes/plugins/isolcpus-device-plugin
 kubernetes/runc
 ldap/ldapscripts
-ldap/nss-pam-ldapd
 ldap/openldap
 livepatch/kpatch
 networking/ifupdown-extra