Reload Dovecot, Postfix and nginx when certificate is renewed

Summary:
Like explained in T2196, we need to reload Dovecot and Postfix.
It will permit them to use the newer certificate possible.

Ref T2196

Test Plan: Deploy on Hervil and try the script to see if it reload well

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T2196

Differential Revision: https://devcentral.nasqueron.org/D4003