Add Support for --label flags

[hertzg]

Adds support for --label flags and introduces a new utility method appendObjectEntries to transform

            "Labels": {
                // ... JSON Object with string key and values
                "traefik.enable": "true",
                "traefik.http.services.some-name.loadbalancer.server.port": "1337"
            }

into

--label 'traefik.enable'='true' --label 'traefik.http.services.some-name.loadbalancer.server.port'='1337'

[nexdrew]

@hertzg Hello 👋

Thanks for submitting this, I apologize for the very long delay in getting your PR reviewed!

I have a couple questions/suggestions, see separate comments below.

Also, we will need to update the expected docker run command in test-cli.js here (i.e. need to add label arguments between these two lines):

rekcod/test/test-cli.js

Lines 36 to 37 in 8dae628

	'--expose 4700/tcp --expose 4702/tcp ' +
	'-e \'DB_USER=postgres\' ' +

If you're still interested in getting this PR merged, let me know what you think. Otherwise, I can recreate your changes on another branch and try to get this merged/released, so everyone using rekcod will get the benefit of your work.

[nexdrew]

Thanks for contributing!

I'm gonna merge this as is. If I want any further changes, I'll add them in a follow-up PR.