Remove more mentions of git submodules

we use ayarn workspaces now

packages/app-shell/README.md

@@ -75,7 +75,7 @@ activities. Handles login, language selection, activity switching, menus etc.
 git clone git@gitlab.tugraz.at:dbp/web-components/toolkit.git
 cd toolkit/packages/app-shell
 
-# install dependencies (make sure you have npm version 4+ installed, so symlinks to the git submodules are created automatically)
+# install dependencies
 yarn install
 
 # constantly build dist/bundle.js and run a local web-server on port 8002 

packages/check-in-place-select/README.md

@@ -33,7 +33,7 @@
 git clone git@gitlab.tugraz.at:dbp/web-components/toolkit.git
 cd toolkit/packages/check-in-place-select
 
-# install dependencies (make sure you have npm version 4+ installed, so symlinks to the git submodules are created automatically)
+# install dependencies
 yarn install
 
 # constantly build dist/bundle.js and run a local web-server on port 8002 

packages/qr-code-scanner/README.md

@@ -39,7 +39,7 @@ after loaded. This attribute is also used to stop the QR code reader or if you d
 git clone git@gitlab.tugraz.at:dbp/web-components/qr-code-scanner.git
 cd qr-code-scanner
 
-# install dependencies (make sure you have npm version 4+ installed, so symlinks to the git submodules are created automatically)
+# install dependencies
 yarn install
 
 # constantly build dist/bundle.js and run a local web-server on port 8002