Create a red-black-tree exercise

[tboychuk]

I believe it's pretty self-explanatory. The first step would be to do the research in order to understand the tree details and implement the tree. Once we have a raw implementation, we can continue the discussion. ❗️

Location & name

2-2-7-red-black-tree

Tests

The only way to provide step-by-step test instructions is to use Reflection AP so I believe we will need to follow the same approach as we did with BST.