ad-auth: Install all required LDAP software

ad-auth/tasks/ldap.yml

 ---
-# file: roles/ad-auth/tasks/ldap.yml
 
-- name: ensure ldap-utils is installed
+- name: Install required LDAP software
   apt:
-    name: ldap-utils
+    name:
+      - ldap-utils
+      - libldap-common
     state: present
+    install_recommends: true
   tags:
     - ldap