[André Pereira (anperei)]

New challenges 2 and 3 of GHCPAppModernization MicroHack

• Created from scratch and added the solutions 2 and 3 files in the respective folders.
• Recreated the existing challenge 2 file and added a new challenge 3 file.
• Updates the finish.md file.
• Updated the readme.md file with this MicroHack's overview.
• Does not take yet into consideration the Challenge 1, to be updated from Lionel, Sameer and Francesco.
• Tried to use as much as possible guidance from here: https://github.com/microsoft/MicroHack/blob/main/CONTRIBUTING.md

(Needs review)

[Carlos Garcia Lalicata (crgarcia12)]

Copilot resolve the merge conflicts in this pull request