Use ng2-pdf-viewer

And remove now-unused safeUrl pipe

src-ui/src/app/pipes/safe.pipe.ts

@@ -1,19 +0,0 @@
-import { Pipe, PipeTransform } from '@angular/core';
-import { DomSanitizer } from '@angular/platform-browser';
-
-@Pipe({
-  name: 'safe'
-})
-export class SafePipe implements PipeTransform {
-
-  constructor(private sanitizer: DomSanitizer) { }
-
-  transform(url) {
-    if (url == null) {
-      return this.sanitizer.bypassSecurityTrustResourceUrl("")
-    } else {
-      return this.sanitizer.bypassSecurityTrustResourceUrl(url);
-    }
-  }
-
-}