[Installation] embed the hyperEDU installation video

[janzandr]

Discussed with @thielfab and @henriDierkes .

Installing the EnMAP-Box for the first time can be challenging. We need to:

• install QGIS
• install the EnMAP-Box plugin
• install plugin dependencies (e.g. Google Earth Engine)
• install Python dependencies

A video showing all the steps may help new users.

[thielfab]

Maybe this is still valid enough? Some minor things here and there have changed, yes. https://www.youtube.com/watch?v=_SNbLmB8aCQ

[janzandr]

Oh yes, we take this video!

[janzandr]

I'll close this here and create a new issue for embedding all the hyperEDU videos inside the RTD website.