Make camera variant primary image

[LongLiveCHIEF]

BREAKING CHANGES for all existing users on their next pull, as this image will replace the existing tagged images once this PR is accepted. We should increased traffic here and on discord for a while. @foosel it would probably be good to add a blog post about this, or include a snippet of info about it in the next blog post. If you want me to author that content, just let me know what approach you want to take.

1.0.0 This will be considered the 1.0.0 release of the official image for octoprint, and will be tagged as such in this git repo once accepted.

Overview

• Changed Docker.camera to Dockerfile
• updated workflows
• updated usage documentation for usage instructions

Changes

• made the container volume for configs /octoprint, which is symlinked to ~/.octoprint (this was /data for the @nunofgs image
• primary container port is now 80 (was formerly 5000 for the default image, and 8888 for the -camera image
• removed cura (will add to feature backlog). Existing implementation was not working anyways, and now that we're s6 based, we need to set it up as a service

Other

• added a web-accissble configuration editor service to the example compose file (see usage docs in README)
• moved the old Dockerfile to /minimal folder, for the eventuality that we'll create a single process image container only octoprint at some point in the future
• @nunofgs this should bring the official image completely in line with your nunofgs/octoprint image, meaning you can now archive github.com/nunofgs/docker-octoprint

closes #67
closes #65
closes #63