register BootstrapVue in app entry point

Author: kajan

AspNetCoreVueMpa.Web/ClientApp/views/home/index/main.js

@@ -1,5 +1,8 @@
 import Vue from 'vue'
 import HelloWorld from "./HelloWorld.vue";
+import { BootstrapVue } from "bootstrap-vue";
+
+Vue.use(BootstrapVue);
 
 const app = new Vue({
   el: '#app',