Feature target metadata ui (#765)

* add metadata tab and popup to target UI

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* send event to update UI

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* send event on target meta data delete and update

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* display selected element name in details layout and metadata popup of UI

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* add comments to explain manual event publishing

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* remove option to hide metadata button in details layout

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* fix typos and refactor

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* fix typos

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

* fix wrong method call

Signed-off-by: Stefan Klotz <stefan.klotz@bosch-si.com>

hawkbit-repository/hawkbit-repository-api/src/main/java/org/eclipse/hawkbit/repository/TargetManagement.java

@@ -764,5 +764,5 @@ public interface TargetManagement {
      *             updated
      */
     @PreAuthorize(SpringEvalExpressions.HAS_AUTH_UPDATE_REPOSITORY)
-    TargetMetadata updateMetaData(@NotEmpty String controllerId, @NotNull MetaData metadata);
+    TargetMetadata updateMetadata(@NotEmpty String controllerId, @NotNull MetaData metadata);
 }