Reminder for expiring certificates

Description of the feature request

A month before signing certificates (iOS) are going to expire, an e-mail should be send to a configurable e-mail or the app owners/admins.

Use case / for what or how I would use it

We are going to manage a lot of different apps with different signing identities. Keeping track of expiring certificates is quite tedious.

Definitely a great idea! Thanks for the #feature-request @matthias.buchetics! :slight_smile: