Implement black-jack concept exercise

[pranasziaukas]

Partially addresses #2428

Implemented

• instructions
• code skeleton
• tests
• example solution
• hints

as seemed appropriate.

Relied on https://bicyclecards.com/how-to-play/blackjack for some typical house rules.

Overall, seems in-line with teaching python operators.

[pranasziaukas]

Refactored the code to not use lists.

[BethanyG]

I left some suggestions and comments. Since this is a draft, I am going to leave them optional and open for discussion. Thank you for submitting this! 🌟

[BethanyG]

@pranasziaukas -- in relation to this, would you also like to pick up PR2456, which is the concept write-up for this exercise?
It is perfectly fine if you do not want to, but we also can't mark this concept exercise live without it, so I am noting that fact here.

[pranasziaukas]

Thank you for reviewing @BethanyG. Since I'm not a native English speaker I gladly accepted the suggested phrasing changes.

in relation to this, would you also like to pick up PR2456, which is the concept write-up for this exercise?

I might pick that one up a bit later. In any case

1. Should the concept write-up work be part of this or a separate PR?
2. Should this remain as a draft PR?

[BethanyG]

Should the concept write-up work be part of this or a separate PR?

It doesn't have to be. It depends on how you want to work. If it feels better to do it in a follow-on PR, that's completely fine. If you do decide to include that work in this PR, I would then make this a large-size PR, and keep it in draft form until we get those concept write-up pieces done.

Should this remain as a draft PR?

Only if you want to include the concept write-up. If not, we can change this to full PR and get it reviewed and merged. The exercise won't go "live" on the site however until the concept introduction.md and about.md write-ups are complete, so we don't have TODO showing on tooltips and pages.

Just let me know how you want to proceed. 😄

[pranasziaukas]

Great!

I guess I prefer working in smaller chunks. Therefore, I'm marking this PR as ready for review as it is.
Once the code is merged, it's only the concept write-ups that need to be done, and those can be naturally addressed in a separate PR.

[BethanyG]

@pranasziaukas - Thank you for this work! 🌟 I think that this PR picked up your follow-on test changes. So merging that one might get weird. Here is me crossing my fingers that it doesn't.

[BethanyG]

aaand we have conflicts. SAD FACE. @pranasziaukas -- can you try fetching from head and rebasing this locally? If all else fails, we'll have to force it, but I am hoping you can resolve this without that. Thanks! 😄

[pranasziaukas]

Should be good now.

The conflict was class BlackJackTest(unittest.TestCase) vs class TestBlackJack(unittest.TestCase) -- I don't quite know/remember where that came from :)

[BethanyG]

It was me. 😞 I changed the name to BlackJackTest to make the output in the UI prettier. It was easier to change the place where Test was in the name than to make a regex that would reliably detect and replace it wherever it went. Now the results will print out with Blackjack > test _____ Apologies for that.

Thank you again for resolving things and for working on this!