feat: Notification Service (#1011)

* WIP - Notification Service

* add snackbar provider into the main App component

* feat: Notification Service

* revert unmodified file

* Update DicomHtmlViewport.js

* update css classnames

* revert toolbarRow

* fix revert toolbarRow

* styles adjustments and hide method

* remove unecessary default options

* minor fixes

* fix long truncated messages

* move SnackbarContext to ui project, rename, export

platform/viewer/src/App.js

@@ -27,6 +27,7 @@ import { BrowserRouter as Router } from 'react-router-dom';
 import { getActiveContexts } from './store/layout/selectors.js';
 import i18n from '@ohif/i18n';
 import store from './store';
+import { SnackbarProvider } from '@ohif/ui';
 
 // Contexts
 import WhiteLabellingContext from './context/WhiteLabellingContext';
@@ -99,7 +100,9 @@ class App extends Component {
                     <WhiteLabellingContext.Provider
                       value={this.props.whiteLabelling}
                     >
-                      <OHIFStandaloneViewer userManager={userManager} />
+                      <SnackbarProvider>
+                        <OHIFStandaloneViewer userManager={userManager} />
+                      </SnackbarProvider>
                     </WhiteLabellingContext.Provider>
                   </Router>
                 </UserManagerContext.Provider>
@@ -116,7 +119,9 @@ class App extends Component {
           <I18nextProvider i18n={i18n}>
             <Router basename={this.props.routerBasename}>
               <WhiteLabellingContext.Provider value={this.props.whiteLabelling}>
-                <OHIFStandaloneViewer />
+                <SnackbarProvider>
+                  <OHIFStandaloneViewer />
+                </SnackbarProvider>
               </WhiteLabellingContext.Provider>
             </Router>
           </I18nextProvider>