Implement getDefaultLoopbackPort() for mounters as required by contract

Author: infeo

src/main/java/org/cryptomator/frontend/webdav/mount/LinuxGioMounter.java

@@ -69,6 +69,11 @@ public Set<MountCapability> capabilities() {
 		return Set.of(MountCapability.LOOPBACK_PORT, MountCapability.MOUNT_TO_SYSTEM_CHOSEN_PATH, MountCapability.VOLUME_ID);
 	}
 
+	@Override
+	public int getDefaultLoopbackPort() {
+		return 42427;
+	}
+
 	@Override
 	public MountBuilder forFileSystem(Path fileSystemRoot) {
 		return new MountBuilderImpl(fileSystemRoot);

src/main/java/org/cryptomator/frontend/webdav/mount/WindowsMounter.java

@@ -48,6 +48,11 @@ public Set<MountCapability> capabilities() {
 		return Set.of(MountCapability.LOOPBACK_PORT, MountCapability.LOOPBACK_HOST_NAME, MountCapability.MOUNT_AS_DRIVE_LETTER, MountCapability.MOUNT_TO_SYSTEM_CHOSEN_PATH, MountCapability.UNMOUNT_FORCED, MountCapability.VOLUME_ID);
 	}
 
+	@Override
+	public int getDefaultLoopbackPort() {
+		return 0; //mounts to a drive letter, hence fixed port is not necessary
+	}
+
 	@Override
 	public MountBuilder forFileSystem(Path path) {
 		return new MountBuilderImpl(path);