Add new sysinv unauthenticated region_id api

This update adds a new sysinv unauthenticated 'region_id' api that
return region_name

curl  http://pxecontroller:6385/v1/isystems/region_id

System inventory will return a dictionary containing the
region_name

{
"region_name": "<system.region_name>"
}

Test Plan:

PASS: Verify success path handling
PASS: Verify multiple dictionary keys

Story: 2011100
Task: 49864

Change-Id: Iaeb77fdd90e5eb06cf9fc9d7da994dd22bfbee14
Signed-off-by: rummadis <ramu.ummadishetty@windriver.com>

api-ref/source/api-ref-sysinv-v1-config.rst

@@ -12592,3 +12592,35 @@ unauthorized (401), forbidden (403), badMethod (405), overLimit (413)
       "success": "kube-config-kubelet applied.",
       "error": ""
    }
+
+***********************************
+Get Region Name
+***********************************
+
+.. rest_method:: GET /v1/isystems/region_id
+
+**Normal response codes**
+
+200
+
+**Error response codes**
+
+serviceUnavailable (503), badRequest (400),
+forbidden (403), badMethod (405)
+
+
+**Response parameters**
+
+.. csv-table::
+   :header: "Parameter", "Style", "Type", "Description"
+   :widths: 20, 20, 20, 60
+
+   "region_name", "plain", "xsd:string", "region name can be default RegionOne or UUID"
+
+::
+
+   {
+      "region_name": "f558ce1b-de27-4132-8ca6-ac7f34ae8d21",
+   }
+
+This operation does not accept a request body.

sysinv/sysinv/sysinv/sysinv/api/config.py

@@ -35,5 +35,6 @@ app = {
                           '/v1/upgrade/[a-zA-Z0-9\-]+/in_upgrade',
                           '/v1/upgrade/[a-zA-Z0-9\-]+/upgrade_in_progress',
                           '/v1/ihosts/[a-zA-Z0-9\:]+/mgmt_ip',
+                          '/v1/isystems/region_id',
                           ]
 }

sysinv/sysinv/sysinv/sysinv/api/controllers/v1/system.py

@@ -16,7 +16,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 #
-# Copyright (c) 2013-2021 Wind River Systems, Inc.
+# Copyright (c) 2013-2021,2024 Wind River Systems, Inc.
 #
 
 import jsonpatch
@@ -24,6 +24,7 @@ import os
 import re
 import pecan
 from pecan import rest
+from pecan import expose
 import six
 import wsme
 from wsme import types as wtypes
@@ -208,6 +209,7 @@ class SystemController(rest.RestController):
     _custom_actions = {
         'detail': ['GET'],
         'mgmtvlan': ['GET'],
+        'region_id': ['GET'],
     }
 
     def __init__(self):
@@ -721,3 +723,9 @@ class SystemController(rest.RestController):
                 else:
                     return interface['vlan_id']
         return None
+
+    @expose('json')
+    def region_id(self):
+        system = pecan.request.dbapi.isystem_get_one()
+        result = {"region_name": system.region_name}
+        return result