Certificate field on MongoDB app connector

**Is your feature request related to a problem? Please describe.**

Hi!

I need to connect my workflow to a managed instance of MongoDB from DigitalOcean and it is not possible to apply the certificate required for this.

**Describe the solution you'd like**
Add a field for uploading the certificate.

**Do you have a workaround?**
Using environment variable can be a way but I'm having difficulties.

**Comparable features in other tools?**

**Additional context**

Thank you!