fix(schematics): always include a common module when generating an nglib

packages/schematics/src/lib/ngfiles/libs/__name__/__sourceDir__/__fileName__.module.ts__tmpl__

@@ -1,6 +1,8 @@
 import { NgModule } from '@angular/core';
+import { CommonModule } from '@angular/common';
 
 @NgModule({
+  imports: [CommonModule]
 })
 export class <%= className %>Module {
 }