[Feature] Non-daemonized `serve` command

[ojii]

Problem or use case

extenddb serve is a bit annoying to use in a container, because the command always daemonizes itself. It would be nice if that functionality could be disabled via command line flag.

Proposed solution

Add a --foreground or --no-daemon flag to the serve command that skips the daemonize logic.

I'd be happy to create a PR for this should such a feature be desirable.

Checklist

• I have searched existing issues and the roadmap for duplicates
• I have described the use case, not just the desired implementation

[marvelefe]

Had the same use case. PR here needs review from a maintainer #129 @LeeroyHannigan @jcshepherd