Additional feature enhancements to nxos_logging (#45844)

* Various changes to nxos_logging.  Plus added purge capibility.

* Made a few new nxapi_logging test cases conditional based on version
and/or platform.

* Addressed PR comments and ansibot shippable.  Fixed up nxos_logging documentation format.

* Addressed ansibot shippable issues with whitespaces and documentation.

* Resolved ansibot codestyle trailing whitespace

lib/ansible/plugins/cliconf/nxos.py

@@ -36,8 +36,20 @@ from ansible.plugins.connection.httpapi import Connection as HttpApi
 class Cliconf(CliconfBase):
 
     def __init__(self, *args, **kwargs):
+        self._module_context = {}
         super(Cliconf, self).__init__(*args, **kwargs)
 
+    def read_module_context(self, module_key):
+        if self._module_context.get(module_key):
+            return self._module_context[module_key]
+
+        return None
+
+    def save_module_context(self, module_key, module_context):
+        self._module_context[module_key] = module_context
+
+        return None
+
     def send_command(self, command, **kwargs):
         """Executes a cli command and returns the results
         This method will execute the CLI command on the connection and return