Add junos_system declartive module and other related change (#25859)

* Add junos_system declartive module and other related change

*  junos_system declartive module
*  integration test for junos_system
*  integration test for net_system (junos platform)
*  pep8 fixes for junos modules
*  move to lxml from elementree for xml parsing as it support
   complete set of xpath api's
*  other minor changes

* Fix CI and doc changes

* Fix unit test failures

* Fix typo in import

* Fix import issue for py2.6

* Add missed Element in import

lib/ansible/modules/network/junos/_junos_template.py

@@ -21,7 +21,6 @@ ANSIBLE_METADATA = {'metadata_version': '1.0',
                     'supported_by': 'community'}
 
 
-
 DOCUMENTATION = """
 ---
 module: junos_template
@@ -87,6 +86,8 @@ options:
     required: false
     default: null
     choices: ['text', 'xml', 'set']
+requirements:
+  - ncclient (>=v0.5.2)
 notes:
   - This module requires the netconf system service be enabled on
     the remote device being managed
@@ -111,11 +112,11 @@ EXAMPLES = """
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.junos import check_args, junos_argument_spec
 from ansible.module_utils.junos import get_configuration, load_config
-from ansible.module_utils.six import text_type
 
 USE_PERSISTENT_CONNECTION = True
 DEFAULT_COMMENT = 'configured by junos_template'
 
+
 def main():
 
     argument_spec = dict(
@@ -137,16 +138,13 @@ def main():
 
     result = {'changed': False, 'warnings': warnings}
 
-    comment = module.params['comment']
-    confirm = module.params['confirm']
     commit = not module.check_mode
     action = module.params['action']
     src = module.params['src']
     fmt = module.params['config_format']
 
     if action == 'overwrite' and fmt == 'set':
-        module.fail_json(msg="overwrite cannot be used when format is "
-            "set per junos-pyez documentation")
+        module.fail_json(msg="overwrite cannot be used when format is set per junos-pyez documentation")
 
     if module.params['backup']:
         reply = get_configuration(module, format='set')