added an interactive fill in the blanks exercise

[abadoni5]

Summary

closes #240

(short description of what does this PR, Issue #, etc.)

Checklist

• [x] Variables, functions and comments are translated to Spanish
• [x] Functions follow underscore notation
• [x] Spell check done & typos fixed
• [x] All python code is PEP8 compliant
• [x] Test coverage with Playwright implemented; locators are Pyhton code
• [x] Reviewers assigned (all peers & at least 1 mentor)

Screenshots

[abadoni5]

@NicolasSandoval @reingart added an interactive fill in the blanks activity for the desk checking exercise

[github-actions[bot]]

Published to http://pyar.github.io/PyZombis/321/index.html

[github-actions[bot]]

Published to http://pyar.github.io/PyZombis/321/index.html