Dynamic Modals (#417)

* Move backdrop and click handler to modal service since they should not be used in web

* Add support for opening modals using ViewContainerRef

angular/src/services/passwordReprompt.service.ts

@@ -0,0 +1,28 @@
+import { Injectable } from '@angular/core';
+
+import { PasswordRepromptService as PasswordRepromptServiceAbstraction } from 'jslib-common/abstractions/passwordReprompt.service';
+
+import { PasswordRepromptComponent } from '../components/password-reprompt.component';
+import { ModalService } from './modal.service';
+
+@Injectable()
+export class PasswordRepromptService implements PasswordRepromptServiceAbstraction {
+    protected component = PasswordRepromptComponent;
+
+    constructor(private modalService: ModalService) { }
+
+    protectedFields() {
+        return ['TOTP', 'Password', 'H_Field', 'Card Number', 'Security Code'];
+    }
+
+    async showPasswordPrompt() {
+        const ref = this.modalService.open(this.component, {allowMultipleModals: true});
+
+        if (ref == null) {
+            return false;
+        }
+
+        const result = await ref.onClosedPromise();
+        return result === true;
+    }
+}