Fixes #527 - Changes for package installation

[ralf401]

No description provided.

[ralf401]

Hi @t-shehab & @byPARSE

I did some (smaller) changes for the install instructions. I left the Redis topic untouched, there is another issue for that which is on hold as we discussed.

I'll add you both as a reviewer. You can download the html-zip from here to review it locally on your machine.

Notes:

• OpenSUSE Leap 15.6 already includes wget, so no need to mention additional packages to install
• Added RHEL in tab titles
• Note for installing Zammad before configuring Elasticsearch already present, see here.
• Removed Firewall commands for OpenSUSE Same firewall as RedHat based distributions -> extended tab

[t-shehab]

Apart from the comment I posted above, the changes look fine for me (without having tested all the commands, assuming you did).

I'd personally prefer a single note that root privileges are required, and then the commands be given without sudo. But that's a matter of opinion, I guess.