More details on installation page

[kreativmonkey]

I think that the installation documentation could be more detailed.

Some improvements are:

• Detailed list of requirements
• Installation example for raspberry pi (as a standalone device running strichliste.org)
• some setting examples

I've worte some of this for my own but i can clean it up and push it to the projekt if it is in your mind.

[schinken]

Hey @kreativmonkey,

would be nice if you can help with the documentation! I'm kind of lost the view as a user and maybe i take some knowledge for granted

Best,
schinken