#173 - Add settings for ffmpeg and ffprobe executable

...nContentPlayer/src/main/resources/lang/base_de.properties

...yer/src/main/resources/view/ContentPlayerSettingsTab.fxml

...inContentPlayer/src/main/resources/view/ZoneSettings.fxml

.../de/tobias/playpad/plugin/content/ContentPluginMain.scala

...plugin/content/player/ContentPlayerWindowController.scala

...n/content/settings/ContentPlayerPluginConfiguration.scala

...ontent/settings/ContentPlayerSettingsViewController.scala

...s/playpad/plugin/content/settings/ContentScreenCell.scala