59334: added validation

src/app/shared/utils/validator.functions.ts

@@ -0,0 +1,7 @@
+import { AbstractControl, ValidatorFn } from '@angular/forms';
+
+export function inListValidator(list: string[]): ValidatorFn {
+  return (control: AbstractControl): {[key: string]: any} | null => {
+    const contains = list.indexOf(control.value) > 0;
+    return contains ? null : {inList: {value: control.value}}  };
+}