Refactoring the DDI Offline Distribution set assignment feature (#1798)

* Refactoring the DDI Offline Distribution set assignment feature

Signed-off-by: Denislav Prinov <denislav.prinov@bosch.com>

* Tests refactoring

Signed-off-by: Denislav Prinov <denislav.prinov@bosch.com>

* make it more visible the featyre is experimental

Signed-off-by: Denislav Prinov <denislav.prinov@bosch.com>

---------

Signed-off-by: Denislav Prinov <denislav.prinov@bosch.com>

hawkbit-rest/hawkbit-ddi-api/src/main/java/org/eclipse/hawkbit/ddi/rest/api/DdiRootControllerRestApi.java

@@ -844,6 +844,7 @@ public interface DdiRootControllerRestApi {
      */
     @Operation(summary = "Set offline assigned version", description = """
         Allow to set current running version.
+        This method is EXPERIMENTAL and may change in future releases.
         """)
     @ApiResponses(value = {
             @ApiResponse(responseCode = "200", description = "Successfully retrieved"),
@@ -858,7 +859,7 @@ public interface DdiRootControllerRestApi {
             @ApiResponse(responseCode = "415", description = "The request was attempt with a media-type which is not supported by the server for this resource.", content = @Content(mediaType = "application/json", schema = @Schema(hidden = true))),
             @ApiResponse(responseCode = "429", description = "Too many requests. The server will refuse further attempts and the client has to wait another second.", content = @Content(mediaType = "application/json", schema = @Schema(hidden = true)))
     })
-    @PostMapping(value = DdiRestConstants.BASE_V1_REQUEST_MAPPING + "/{controllerId}/"
+    @PutMapping(value = DdiRestConstants.BASE_V1_REQUEST_MAPPING + "/{controllerId}/"
             + DdiRestConstants.INSTALLED_BASE_ACTION, consumes = {
             MediaType.APPLICATION_JSON_VALUE, DdiRestConstants.MEDIA_TYPE_CBOR })
     ResponseEntity<Void> setAsssignedOfflineVersion(@Valid DdiAssignedVersion ddiAssignedVersion,