added missing decorator for classes that use Angular features

src/app/process-page/form/process-parameters/parameter-value-input/value-input.component.ts

@@ -1,9 +1,12 @@
-import { EventEmitter, Input, Output, Directive } from '@angular/core';
+import { Component, EventEmitter, Input, Output } from '@angular/core';
 
 /**
  * Abstract class that represents value input components
  */
-@Directive()
+@Component({
+  selector: 'ds-value-input',
+  template: ''
+})
 export abstract class ValueInputComponent<T> {
   @Input() index: number;
   /**