Refactor common network shared and platform utils code into package (#33452)

* Refactor common network shared and platform specific code into package (part-1)

As per proposal #76 refactor common network shared and platform specific
code into sub-package.
https://github.com/ansible/proposals/issues/76

*  ansible.module_utils.network.common - command shared functions
*  ansible.module_utils.network.{{ platform }} - where platform is platform specific shared functions

*  Fix review comments

* Fix review comments

lib/ansible/module_utils/network/ordnance/ordnance.py

@@ -0,0 +1,19 @@
+_DEVICE_CONFIGS = {}
+
+
+def get_config(module, flags=None):
+    flags = [] if flags is None else flags
+
+    cmd = 'show running-config '
+    cmd += ' '.join(flags)
+    cmd = cmd.strip()
+
+    try:
+        return _DEVICE_CONFIGS[cmd]
+    except KeyError:
+        rc, out, err = module.exec_command(cmd)
+        if rc != 0:
+            module.fail_json(msg='unable to retrieve current config', stderr=err)
+        cfg = str(out).strip()
+        _DEVICE_CONFIGS[cmd] = cfg
+        return cfg