Improve website blog layout

[pmig]

Is your feature request related to a problem? Please describe. Currently our blog layout is basically the default one and not really appealing.

Describe the solution you'd like After the introduction of https://github.com/glasskube/glasskube/pull/874 and the image attribute for blog posts, we can also revamp our /blog page. Headlamp (also built with Docusaurus) has a very very nice Design we should get a lot of inspiration from: https://headlamp.dev/blog

Additional context @jakepage91 might be needed to add the image attribute to all past blog posts.