network/exos: add exos_facts module (#43210)

Add exos_facts module. Known limitations at this time include:
   - Interface MTU is not reported.
   - Only primary interface IP is reported.

Add basic unit tests for the exos_facts module.

An EXOS CLI prompt can be prefixed with '! ' (shutting down), '* '
(running configuration does not match saved configuration), and
can include various status tokens within parentheses after these
prefixes. Update prompt regex to accept valid CLI prompts.

lib/ansible/plugins/terminal/exos.py

@@ -28,7 +28,7 @@ from ansible.plugins.terminal import TerminalBase
 class TerminalModule(TerminalBase):
 
     terminal_stdout_re = [
-        re.compile(br"[\r\n][\w\+\-\.:\/\[\]]+(?:\([^\)]+\)){0,3} (?:[>#]) ?$")
+        re.compile(br"[\r\n](?:! )?(?:\* )?(?:\(.*\) )?(?:Slot-\d+ )?\S+\.\d+ (?:[>#]) ?$")
     ]
 
     terminal_stderr_re = [