refractor: add material module

Add custom shared module for angular material and flex layout.

src/app/core/core.module.ts

@@ -2,6 +2,8 @@ import { NgModule, Optional, SkipSelf } from '@angular/core';
 import { CommonModule } from '@angular/common';
 import { HTTP_INTERCEPTORS, HttpClient, HttpClientModule } from '@angular/common/http';
 import { RouteReuseStrategy, RouterModule } from '@angular/router';
+
+// To be removed, replace by shared material module
 import { LayoutModule } from '@angular/cdk/layout';
 import { FlexLayoutModule } from '@angular/flex-layout';