Change favorite certificate CLI

[mrmarkuz (Markus Neuberger)]

Here are some docs:
http://docs.nethserver.org/projects/nethserver-devel/en/v7/certificate_management.html

Here is a discussion about cert scripting:

SSL certificates for Samba AD (NSDC host)

When a certificate is renewed (including LE one) the event certificate-update is called. You can add a script inside it /etc/e-smith/events/certificate-update