Migration to typescript: first step

Add vue cli typescript support
Rename .js to .ts
Use class and annotations in App and NavBar
Add tslint

js/src/graphql/upload.ts

@@ -0,0 +1,10 @@
+import gql from 'graphql-tag';
+
+export const UPLOAD_PICTURE = gql`
+    mutation {
+        uploadPicture(file: "file") {
+            url,
+            url_thumbnail
+        }
+    }
+`;