feat(api): accept rule config block string in playground

Update playground request to take rules as a string and parse
either YAML list or DSL config, with tests and swagger updates.

internal/api/v1/docs/swagger.yaml

@@ -905,9 +905,7 @@ definitions:
       mockResponse:
         $ref: '#/definitions/MockResponse'
       rules:
-        items:
-          $ref: '#/definitions/routeApi.RawRule'
-        type: array
+        type: string
     required:
     - rules
     type: object
@@ -1858,15 +1856,6 @@ definitions:
       uptime:
         type: string
     type: object
-  routeApi.RawRule:
-    properties:
-      do:
-        type: string
-      name:
-        type: string
-      "on":
-        type: string
-    type: object
   routeApi.RoutesByProvider:
     additionalProperties:
       items: