Port eos tests to network_cli (#33586)

* Add eos and fix tests to run multiple connections

* Update tests to report connection

* Add missing START messages

* Fix unspecified connection

* Python 3 updates

Exceptions don't have `.message` in Python 3

* Override `become` when using `connection=local`

* Slight restructuring to make eapi easier later on

* Move eapi toggle to prepare_eos
* Pull out connection on eapi tasks

lib/ansible/plugins/action/eos_config.py

@@ -41,7 +41,7 @@ class ActionModule(_ActionModule):
             try:
                 self._handle_template()
             except ValueError as exc:
-                return dict(failed=True, msg=exc.message)
+                return dict(failed=True, msg=to_text(exc))
 
         result = super(ActionModule, self).run(tmp, task_vars)
 
@@ -55,7 +55,7 @@ class ActionModule(_ActionModule):
 
         # strip out any keys that have two leading and two trailing
         # underscore characters
-        for key in result.keys():
+        for key in list(result.keys()):
             if PRIVATE_KEYS_RE.match(key):
                 del result[key]