I don't know about another ready-to-use application that allows you to trigger QDS tasks from anywhere at any time (except for the one that lets SAP trigger QDS tasks)
The best alternative I can suggest and that will perfectly integrate in your specific environment is to write your own application or service that uses the QMS API to control, start and track tasks.
1. Need to share data with QV application - upon arrival data, task needs to be triggered.
2. If we need to trigger QV task based on some external event then we can ask delegate/source system to create Zero KB (kind of token) so we can poll the folder and trigger the task
Used this approach for above use cases: Triggering task on QMC upon file arrival | QlikTab