junos_linkagg implementation and junos modules refactor (#26587)

* junos_linkagg implementation and junos modules refactor

*  junos_linkagg implementation
*  junos_linkagg integration test
*  net_linkagg integration test for junos
*  decouple `load_config` and `commit` operations,
   to allow single commit (in case on confirm commit) and
   to perform batch commit (multiple `load_config` followed by single
   `commit`)
*  Other related refactor

* Fix CI issues

* Fix unit test failure

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

@@ -129,9 +129,9 @@ EXAMPLES = """
 """
 
 RETURN = """
-diff:
+diff.prepared:
   description: Configuration difference before and after applying change.
-  returned: when configuration is changed.
+  returned: when configuration is changed and diff option is enabled.
   type: string
   sample: >
         [edit interfaces]
@@ -141,9 +141,10 @@ diff:
 """
 import collections
 
-from ansible.module_utils.junos import junos_argument_spec, check_args
 from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.junos import junos_argument_spec, check_args
 from ansible.module_utils.junos import load_config, map_params_to_obj, map_obj_to_ele
+from ansible.module_utils.junos import commit_configuration, discard_changes, locked_config
 
 try:
     from lxml.etree import tostring
@@ -225,21 +226,22 @@ def main():
 
     validate_param_values(module, param_to_xpath_map)
 
-    want = list()
-    want.append(map_params_to_obj(module, param_to_xpath_map))
-
+    want = map_params_to_obj(module, param_to_xpath_map)
     ele = map_obj_to_ele(module, want, top, choice_to_value_map)
 
-    kwargs = {'commit': not module.check_mode}
-    kwargs['action'] = 'replace'
+    with locked_config(module):
+        diff = load_config(module, tostring(ele), warnings, action='replace')
 
-    diff = load_config(module, tostring(ele), warnings, **kwargs)
+        commit = not module.check_mode
+        if diff:
+            if commit:
+                commit_configuration(module)
+            else:
+                discard_changes(module)
+            result['changed'] = True
 
-    if diff:
-        result.update({
-            'changed': True,
-            'diff': diff,
-        })
+            if module._diff:
+                result['diff'] = {'prepared': diff}
 
     module.exit_json(**result)