See https://framacolibri.org/t/listen-to-unix-socket-instead-of-localhost-9000/5348

The support ends on December 2019: https://github.com/nodejs/Release#release-schedule

* Update CentOS 7 dependencies install

Add initialization for postgresql database (else there is an error when starting postresql service).
Enable Redis and PostreSQL services.
Replace "service" by "systemctl" (systemd).

Tested in local on a fresh CentOS 7 install.

* Add wget package to install

Add wget package to install

* Add since parameter to peertube-import-videos

* PR remarks + --until <date>