[Documentation][zos_backup_restore] Standarize doc-strings on modules/zos_backup_restore.py (#1342)

* Standarize doc-strings on modules/zos_backup_restore.py

* Create changelog fragment

* Modify google style to numpy

* Standarize numpy style

Author: IsaacVRey

changelogs/fragments/1342-update-docstring-zos_backup_restore.yml

@@ -0,0 +1,3 @@
+trivial:
+  - zos_backup_restore - Updated docstrings to numpy style for visual aid to developers.
+    (https://github.com/ansible-collections/ibm_zos_core/pull/1342).