Automatically validate that DEV_INSTALL.md works

[frcroth]

Detailed Description

• Parse install steps for ubuntu from DEV_INSTALL.md (optional, otherwise create Dockerfile directly)
• Run install steps in docker container from ubuntu:22.04
• Start webknossos and perform smoke test

Context

• Specific to long-running jobs (set jobsEnabled=true in application.conf)
• Specific to webknossos.org (set isDemoInstance=true in application.conf)

[fm3]

This could be something for the nightly test