Label printing fix (#489)

* Add check for modern label printing interface

* Update getLabelTemplates

* Fix typo

* Refactor / simplify

* Revert parameter type

* Update version number and release notes

* Refactor label printing function

- Will require some cleanup in the future
- Still needs testing

* Fix for modern printing

* Typo fix

lib/settings/about.dart

@@ -194,7 +194,7 @@ class InvenTreeAboutWidget extends StatelessWidget {
     tiles.add(
       ListTile(
         title: Text(L10().documentation),
-        subtitle: Text("https://docs.inventree.org"),
+        subtitle: Text("https://docs.inventree.org/app"),
         leading: FaIcon(FontAwesomeIcons.book, color: COLOR_ACTION),
         onTap: () {
           _openDocs();