add stub for vault conversion (hub to local)

src/main/resources/fxml/convertvault_hubtolocal_start.fxml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<?import javafx.scene.layout.*?>
+
+<?import javafx.geometry.Insets?>
+<?import javafx.scene.control.ButtonBar?>
+<?import javafx.scene.control.Button?>
+<VBox xmlns:fx="http://javafx.com/fxml"
+	  xmlns="http://javafx.com/javafx"
+	  fx:controller="org.cryptomator.ui.convertvault.HubToLocalStartController"
+	  minWidth="350"
+	  minHeight="280"
+	  spacing="12"
+	  alignment="TOP_LEFT">
+	<padding>
+		<Insets topRightBottomLeft="24"/>
+	</padding>
+	<children>
+		<fx:include fx:id="recoveryKeyValidate" source="recoverykey_validate.fxml"/>
+
+		<Region VBox.vgrow="ALWAYS"/>
+
+		<VBox alignment="BOTTOM_CENTER" VBox.vgrow="ALWAYS">
+			<ButtonBar buttonMinWidth="120" buttonOrder="+CX">
+				<buttons>
+					<Button text="%generic.button.cancel" ButtonBar.buttonData="CANCEL_CLOSE" cancelButton="true" onAction="#close"/>
+					<Button text="%generic.button.next" ButtonBar.buttonData="NEXT_FORWARD" defaultButton="true" onAction="#convert" disable="${!controller.validateController.recoveryKeyCorrect}"/>
+				</buttons>
+			</ButtonBar>
+		</VBox>
+	</children>
+</VBox>

src/main/resources/fxml/vault_options_hub.fxml

@@ -3,8 +3,6 @@
 <?import org.cryptomator.ui.controls.FontAwesome5IconView?>
 <?import javafx.geometry.Insets?>
 <?import javafx.scene.control.Button?>
-<?import javafx.scene.control.Label?>
-<?import javafx.scene.layout.Region?>
 <?import javafx.scene.layout.VBox?>
 <VBox xmlns:fx="http://javafx.com/fxml"
 	  xmlns="http://javafx.com/javafx"
@@ -14,4 +12,10 @@
 	<padding>
 		<Insets topRightBottomLeft="12"/>
 	</padding>
+
+	<Button fx:id="convertToLocalButton" text="TODO Convert" onAction="#startConversion">
+		<graphic>
+			<FontAwesome5IconView glyph="ANCHOR"/>
+		</graphic>
+	</Button>
 </VBox>