Add service-desk dependencies in documentation

[davidcoutadeur]

It would be nice to have an exhaustive dependencies listing in install docs:

• https://service-desk.readthedocs.io/en/stable/installation.html#debian-ubuntu
• https://service-desk.readthedocs.io/en/stable/installation.html#centos-redhat

Especially about new php requirement >= 7.4 and about smarty version

[radasys]

Hi,

I have installed yesterday Service Desk on Ubuntu 22.04.2 and it installed PHP, Apache2 and other packages without issues.

However, I had an issue with Smarty3. It seems there is something odd with the package downloaded through apt (I had error 500 when loading index.php).

I followed advice on https://github.com/ltb-project/self-service-password/issues/681 and installed Smarty 3.1.47-2, then Service Desk worked fine.

So maybe a Warning message like the one below may help:

"You may need to install first the package smarty3 (version 3.1.47-2 or higher) which, at least in Debian 11/Ubuntu 22.04.2 is not in official repositories. Please check this Github issue for more information"

Just a suggestion! Thanks!