Move all the sample containers to `play-with-docker` organization

[Privat33r-dev]

This way many issues can be avoided.
#238 updated the doc, but the issue persists on the sample repo (which is fetched in the room as a part of learning process),
#247 shows another issue: the repo was updated and we describe in tutorial 6 services, while they removed 1 and it's now 5 services. It leave the reader confused and maybe even frustrated.

[marcosnils]

cc @mikesir87 we need your input here also 🙏

[Privat33r-dev]

And another example: dockersamples/linux_tweet_app#12