replacing hardcoded descriptions by reference to strings.properties for addvault welcome controller

main/ui/src/main/resources/fxml/addvault_welcome.fxml

@@ -15,12 +15,12 @@
 		<Insets top="12" right="12" bottom="12" left="12"/>
 	</padding>
 	<children>
-		<Label text="TODO new vault or existing vault?"/>
+		<Label text="%addvaultwizard.welcome.instruction"/>
 
 		<HBox spacing="12">
-			<Button text="TODO new vault" onAction="#createNewVault"/>
+			<Button text="%addvaultwizard.welcome.newButton" onAction="#createNewVault"/>
 
-			<Button text="TODO existing vault" onAction="#chooseExistingVault"/>
+			<Button text="%addvaultwizard.welcome.existingButton" onAction="#chooseExistingVault"/>
 		</HBox>
 	</children>
 </VBox>

main/ui/src/main/resources/i18n/strings.properties

@@ -1,3 +1,7 @@
+#add Vault Dialogues
+addvaultwizard.welcome.instruction=TODO new vault or existing vault?
+addvaultwizard.welcome.newButton=TODO new vault
+addvaultwizard.welcome.existingButton=TODO exising vault
 addvaultwizard.existing.instruction=Please choose the masterkey.cryptomator file of your existing vault. The directory contain it will be displayed. 
 addvaultwizard.existing.filePickerTitle=Open Masterkey File
 addvaultwizard.new.insertName=Please enter a name for the vault.