Create guide for adding certain things to project (documentation)

[thefakejj]

Examples:

• Creating new task in editor
• Document what pupu can do:
  • liiku, sano, kysy, laske, luo, poista
  • porkkana, kivi
  • terms: collectible, obstacle, grid object
• Creating new game mode
  • Creating new win condition
• Creating new theme
• Creating new grid object

[VP-MaxHax]

Guide for making new task and overall guide to use task editor done.

https://github.com/Pelialusta-Python-ohjelmointikurssille/pupupeli/blob/main/documentation/task_editor.md

[VP-MaxHax]

Guide that explains usage of all character commands. (Document what pupu can do)

https://github.com/Pelialusta-Python-ohjelmointikurssille/pupupeli/blob/main/documentation/user_commands.md

[epertt]

Creating new win condition added in #259