[management] Add CreatedAt field to Peer and PeerBatch models (#4371)

[management] Add CreatedAt field to Peer and PeerBatch models (#4371)

shared/management/http/api/openapi.yml

@@ -369,6 +369,11 @@ components:
         - $ref: '#/components/schemas/PeerMinimum'
         - type: object
           properties:
+            created_at:
+              description: Peer creation date (UTC)
+              type: string
+              format: date-time
+              example: "2023-05-05T09:00:35.477782Z"
             ip:
               description: Peer's IP address
               type: string
@@ -471,6 +476,7 @@ components:
             - connected
             - connection_ip
             - country_code
+            - created_at
             - dns_label
             - geoname_id
             - groups
@@ -544,11 +550,17 @@ components:
         - $ref: '#/components/schemas/Peer'
         - type: object
           properties:
+            created_at:
+              description: Peer creation date (UTC)
+              type: string
+              format: date-time
+              example: "2023-05-05T09:00:35.477782Z"
             accessible_peers_count:
               description: Number of accessible peers
               type: integer
               example: 5
           required:
+            - created_at
             - accessible_peers_count
     SetupKeyBase:
       type: object