Add Update Channel to UI and Enum (change package of update classes)

...all/assets/de/tobias/playpad/assets/lang/ui_de.properties

...ssets/de/tobias/playpad/assets/view/option/updateTab.fxml

PlayWall/src/de/tobias/playpad/PlayPadMain.java

PlayWall/src/de/tobias/playpad/PlayPadUpdater.java

...src/de/tobias/playpad/viewcontroller/cell/UpdateCell.java

...laypad/viewcontroller/option/UpdateTabViewController.java

PlayWallCore/src/de/tobias/playpad/update/Updatable.java

PlayWallCore/src/de/tobias/playpad/update/UpdateChannel.java

...allCore/src/de/tobias/playpad/update/UpdateRegistery.java