Test system (#22420)

* ios_system

* tests for ios_system

* tests for *_system

* working ios_system on cli

* Typo

* Loopback10 (single word, upeprcase)

* Revert docs changes

* Working iosxr_system tests

* eos, not nxos

* nxos_system

test/integration/targets/iosxr_system/tasks/cli.yaml

@@ -0,0 +1,16 @@
+---
+- name: collect all cli test cases
+  find:
+    paths: "{{ role_path }}/tests/cli"
+    patterns: "{{ testcase }}.yaml"
+  register: test_cases
+  delegate_to: localhost
+
+- name: set test_items
+  set_fact: test_items="{{ test_cases.files | map(attribute='path') | list }}"
+
+- name: run test case
+  include: "{{ test_case_to_run }}"
+  with_items: "{{ test_items }}"
+  loop_control:
+    loop_var: test_case_to_run