Switch to image built by melange and apko

TODO:

• Update Readme
• Make the container scanning use the SBOM generated by apko instead of the image itself - [ ] Change project path and references Not possible as i don't want to delete all previously built images
• Figure out how this should be tagged (keep the old schema or switch to a nitter-commit-sha approach?)

With this nitter gets build by melange into an apk package which is then installed into a container by apko. This brings two impactful changes with it:

• The whole build time is decreased from ~7m to ~5m, 1m of that is because of the ommitted tagging steps
• s6 is packaged in the container and it takes care of process reaping and signal processing so that the container does not have to be force stopped anymore