The plugin should fall back to using some default project settings (appPath: 'app', appResourcesPath: 'app/App_Resources') if {N} CLI is not globally installed.

Steps to test:

1. Create new {N} project:

tns create my-project
cd my-project

2. Uninstall {N} CLI:

npm uninstall -g nativescript

If you're using nvm it wouble be enough to set up an empty workspace by installing a new node version. For example - nvm install 9.9.0.

3. Install nativescript-dev-webpack from the current PR's branch:

npm i nativescript/nativescript-dev-webpack#sis0k0/return-if-no-tns

Expected behaviour
The plugin should be installed successfully and vendor.ts, vendor-platform.android.ts and vendor-platform.ios.ts should be added inside the app/ dir.

Current behaviour
The postinstall script fails while trying to find globally installed tns.