* optional fix for https port 5284 error

https://community.jitsi.org/t/no-certificate-present-in-ssl-tls-configuration-for-https-port-5284/47836/7

* usage of sudo and systemctl made more consistent

* jigasi download url changed to stable

Jigasi download url changed. Is this required in addition to apt install jigasi as part of the quick install guide?

* wget/dpkg removed from jagasi instructions