Make DockStarter work with CoreOS (immutable filesystem, no traditional package manager)

[dylanmtaylor]

Pull request

Purpose Closes #1730.

Tested on ucore-hci from the Universal Blue project. Manual workaround needed for docker compose plugin:

DOCKER_CONFIG=${DOCKER_CONFIG:-$HOME/.docker}
mkdir -p $DOCKER_CONFIG/cli-plugins
curl -SL https://github.com/docker/compose/releases/download/v2.24.5/docker-compose-linux-x86_64 -o $DOCKER_CONFIG/cli-plugins/docker-compose
chmod +x $DOCKER_CONFIG/cli-plugins/docker-compose

I also set SELinux to permissive. After that, it worked perfectly and all my containers spun up. :-)

Approach How does this change address the problem?

• Uses $HOME/bin instead of /usr for the filesystem
• Doesn't fail hard if it detects no supported package manager, instead checking if the commands we need are there.

Open Questions and Pre-Merge TODOs Check all boxes as they are completed

• [x] Use github checklists. When solved, check the box and explain the answer.

Learning Describe the research stage Links to blog posts, patterns, libraries or addons used to solve this problem

Requirements Check all boxes as they are completed

• [x] These changes meet the standards for contributing.
• [x] I have read the code of conduct.

[nemchik]

Changing branch and merging so I can stage in some additional adjustments.