Refactor project related classes

...scala/de/tobias/playpad/server/model/project/Design.scala

...in/scala/de/tobias/playpad/server/model/project/Pad.scala

...n/scala/de/tobias/playpad/server/model/project/Page.scala

...n/scala/de/tobias/playpad/server/model/project/Path.scala

...cala/de/tobias/playpad/server/model/project/Project.scala

...e/tobias/playpad/server/model/project/settings/Fade.scala

...s/playpad/server/model/project/settings/PadSettings.scala

...cala/de/tobias/playpad/server/project/utils/JsonDef.scala

.../tobias/playpad/server/server/project/ProjectDelete.scala

.../de/tobias/playpad/server/server/project/ProjectGet.scala

...de/tobias/playpad/server/server/project/ProjectList.scala

...laypad/server/server/project/ProjectModificationGet.scala

...de/tobias/playpad/server/server/project/ProjectPost.scala

...aypad/server/server/project/sync/ProjectSyncHandler.scala

...rver/project/sync/listener/design/DesignAddListener.scala

...r/project/sync/listener/design/DesignUpdateListener.scala

...ver/server/project/sync/listener/pad/PadAddListener.scala

...r/server/project/sync/listener/pad/PadClearListener.scala

.../server/project/sync/listener/pad/PadRemoveListener.scala

.../server/project/sync/listener/pad/PadUpdateListener.scala