[ADF-3874] icon component (#4112)

* adf-icon component

* demo shell example page

* add docs

* integration with thumbnail service

demo-shell/src/app/components/icons/icons.module.ts

@@ -0,0 +1,39 @@
+/*!
+ * @license
+ * Copyright 2016 Alfresco Software, Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { NgModule } from '@angular/core';
+import { Routes, RouterModule } from '@angular/router';
+import { CommonModule } from '@angular/common';
+import { CoreModule } from '@alfresco/adf-core';
+import { IconsComponent } from './icons.component';
+
+const routes: Routes = [
+    {
+      path: '',
+      component: IconsComponent
+    }
+];
+
+@NgModule({
+    imports: [
+        CommonModule,
+        CoreModule.forChild(),
+        RouterModule.forChild(routes)
+    ],
+    declarations: [IconsComponent]
+})
+export class AppIconsModule {}