Adding new preview version for DNC API to expose optional "purpose" p…

…arameter when creating a controller (#24097)

* creating new preview version "2013-05-18-preview" for DNC API

* updating api version in files

* adding purpose flag

* updating readme files

* moving "purpose" to custom props section

* setting default for back compat

* fix tests

* adding location header to DELETE APIs

* Removing 202 for deletes since not used in our RP

* removing long running op flag from DELETE apis

* rollback 202 changes for DELETE APIs and adding the LRO Location header

specification/dnc/resource-manager/Microsoft.DelegatedNetwork/preview/2023-05-18-preview/common-types.json

@@ -0,0 +1,49 @@
+{
+  "swagger": "2.0",
+  "info": {
+    "version": "2023-05-18-preview",
+    "title": "DNC",
+    "description": "DNC web api provides way to create, get and delete dnc controller"
+  },
+  "host": "management.azure.com",
+  "schemes": [
+    "https"
+  ],
+  "consumes": [
+    "application/json"
+  ],
+  "produces": [
+    "application/json"
+  ],
+  "security": [
+    {
+      "azure_auth": [
+        "user_impersonation"
+      ]
+    }
+  ],
+  "securityDefinitions": {
+    "azure_auth": {
+      "type": "oauth2",
+      "authorizationUrl": "https://login.microsoftonline.com/common/oauth2/authorize",
+      "flow": "implicit",
+      "description": "Azure Active Directory OAuth2 Flow",
+      "scopes": {
+        "user_impersonation": "impersonate your user account"
+      }
+    }
+  },
+  "paths": {},
+  "definitions": {
+    "controllerDetails": {
+      "description": "controller details",
+      "type": "object",
+      "properties": {
+        "id": {
+          "description": "controller arm resource id",
+          "type": "string"
+        }
+      }
+    }
+  }
+}