consider use other source of package icons

[jmlich]

Currently, we have all icons extracted into /static/. It might be better to use third party repository (i.e. to get rid of something we need to maintain)

We can use this:

<img src="https://apps.fedoraproject.org/packages/images/icons/{{ app.get_pkgname }}.png" alt="{{ app.get_pkgname }}"/>

[jmlich]

We should explore the quality of the source first. For example: mentioned source of icons don't have icon for subsurface application.