IPAAnsibleModule: add support for ldap_cache configuration.

This patch adds support for configuring IPA API connection use of
LDAP cache. It adds a new variable 'ipaapi_ldap_cache' to the base
module, and provides the variable documentation in its doc fragment.

plugins/module_utils/ansible_freeipa_module.py

@@ -629,6 +629,7 @@ else:
             ipaapi_context=dict(
                 type="str", required=False, choices=["server", "client"],
             ),
+            ipaapi_ldap_cache=dict(type="bool", default="True"),
         )
 
         def __init__(self, *args, **kwargs):