Adds a script which install certificates from let's encrypt.
The script looks for nginx, apache2 or jetty configuration and edits the first one found. Nginx and apache2 will be reloaded, while jvb will be stopped, configured and started again.
Now the web app can be installed separately from jicofo and jitsi-videobridge, or can be installed on machine running nginx or apache. Currently only nginx will be configured and apache config is left to user. Later we can add and the apache config. Renames jitsi-meet to jitsi-meet-web (just the web content) and jitsi-meet-web-config (configuring jetty, nginx or apache). A new jitsi-meet package will be introduced, a meta package depending on jicofo, jvb and the current packages.
Updates meet default installation. Removes nginx dependency and adds openjdk-8 in order to activate multiplexing inside jvb and use its jetty to serve meet. Updates will not touch current configuration which will continue using nginx.
damencho