remove help button when reaching footer by scroll, update submodule

src/app/app.component.ts

@@ -1,4 +1,4 @@
-import {Component, ViewChild} from '@angular/core';
+import {Component, ElementRef, ViewChild} from '@angular/core';
 import {ActivatedRoute, NavigationEnd, Router} from '@angular/router';
 
 import {EnvProperties} from './openaireLibrary/utils/properties/env-properties';
@@ -60,11 +60,11 @@ import {ResourcesService} from "./openaireLibrary/monitor/services/resources.ser
                                      points="7 4 13 10 7 16"></polyline></svg>
             </span></a>
       </cookie-law>
+      <bottom #bottom *ngIf="properties && showMenu" id="bottom" [grantAdvance]="false"
+			[properties]="properties"></bottom>
       <quick-contact #quickContact *ngIf="showQuickContact && contactForm" (sendEmitter)="send($event)"
                      [contactForm]="contactForm" [sending]="sending" [images]="images" [contact]="'Help'"
                      [organizationTypes]="organizationTypes"></quick-contact>
-      <bottom *ngIf="properties && showMenu" id="bottom" [grantAdvance]="false"
-              [properties]="properties"></bottom>
       <modal-alert #modal [overflowBody]="false"></modal-alert>
     </div>
   `
@@ -92,6 +92,7 @@ export class AppComponent {
   public sending = false;
   @ViewChild('modal') modal: AlertModal;
   @ViewChild('quickContact') quickContact: QuickContactComponent;
+	@ViewChild('bottom', {read: ElementRef}) bottom: ElementRef;
   private subscriptions: any[] = [];
 	public stakeholderEntities = StakeholderEntities;
   
@@ -137,6 +138,27 @@ export class AppComponent {
       this.showQuickContact = display;
     }));
   }
+
+	createObservers() {
+		let options = {
+			root: null,
+			rootMargin: '300px',
+			threshold: 1.0
+		};
+		let intersectionObserver = new IntersectionObserver(entries => {
+			entries.forEach(entry => {
+        if (entry.isIntersecting && this.showQuickContact) {
+          this.showQuickContact = false;
+          this.quickContactService.setDisplay(this.showQuickContact);
+        } else if (!entry.isIntersecting && !this.showQuickContact) {
+          this.showQuickContact = true;
+          this.quickContactService.setDisplay(this.showQuickContact);
+        }
+      });
+		}, options);
+		intersectionObserver.observe(this.bottom.nativeElement);
+		this.subscriptions.push(intersectionObserver);
+	}
   
   public ngOnDestroy() {
     this.subscriptions.forEach(value => {
@@ -168,6 +190,9 @@ export class AppComponent {
       new MenuItem("", "Contact us", "https://beta.openaire.eu/contact-us", "", false, [], [], {})
     ];
     this.showMenu = true;
+		setTimeout(() => {
+			this.createObservers();
+		})
   }
   
   public setUserMenu() {

src/app/openaireLibrary

@@ -1 +1 @@
-Subproject commit bcaf7166a5023c1538058473b8606519cedf8b7a
+Subproject commit 4216be29cd8eb993831cc96e5540b8631333856c