Add Page Titles Everywhere (#177)

Add page titles everywhere

Add global mixin to set page title

Co-authored-by: kolaente <k@knt.li>
Reviewed-on: https://kolaente.dev/vikunja/frontend/pulls/177

src/helpers/setTitle.js

@@ -0,0 +1,9 @@
+
+export const setTitle = title => {
+	if (typeof title === 'undefined' || title === '') {
+		document.title = 'Vikunja'
+		return
+	}
+
+	document.title = `${title} | Vikunja`
+}