added tray icon, refactored dagger component graph:

singleton -> tray -> fxapplication -> mainwindow

main/ui/src/test/java/org/cryptomator/ui/controls/Foo.java

@@ -0,0 +1,27 @@
+package org.cryptomator.ui.controls;
+
+import javafx.beans.property.SimpleStringProperty;
+import javafx.beans.property.StringProperty;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.time.Duration;
+import java.util.concurrent.CountDownLatch;
+
+public class Foo {
+	
+	@Test
+	public void foo() {
+		StringProperty str = new SimpleStringProperty("foo");
+		CountDownLatch done = new CountDownLatch(1);
+		str.addListener(observable -> {
+			Assertions.assertEquals("bar", str.get());
+			done.countDown();
+		});
+		str.set("bar");
+		Assertions.assertTimeoutPreemptively(Duration.ofMillis(100), () -> {
+			done.await();
+		});
+	}
+
+}