Updating the kata rank descriptions.

[Captain-Quack]

• Removed examples that aren't relevant (e.g There is currently only one task under the Concurrency tag)
• Added links to kata showing examples of the topics. I tried to pick quality kata without, but a few need to be updated to new js and python frameworks.
• I changed the color descriptions to be a little less harsh (Beginner->Beginner, Novice->Intermediate, Competent->Advanced, Proficient->Expert)
• I mixed up the word variety a bit. I am in my 1st year of programming; you might want to review the Kyu challenge-level descriptions for accuracy (e.g Idk if 2kyu is actually a professional rank. )
• Let me know if I need to ask the authors for permission, I understand if someone doesn't want their kata displayed for example.