interface for saving and loading a game

[pcichowski]

Pull request review checklist 📝 ✅

This is a checklist that helps conduct a pull request review properly. These points are required to merge the PR

• There are no merge conflicts

• The pull request is named accordingly (description of the functionality - it
  will be visible in the changelog later)

• Every task requirement (from Jira) is done

• The app runs, it boots up properly (e.g. no syntax errors)

• The proposed functionality is working properly (you need to pull this branch
  and check for yourself)

• Each function, class or functionality is properly documented
  (short description of what it does, parameters or return values if they need
  any explanation)

[github-actions]

Test Results

42 tests  ±0   42 ✔️ ±0   7s ⏱️ -1s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 94faf71. ± Comparison against base commit ff75632.

♻️ This comment has been updated with latest results.

[pcichowski]

aktualny status: zapisywanie stanu gry za pomocą komendy /pause działa, okazuje się natomiast że ładowanie gry jest dość problematyczne i będzie trzeba to przemyśleć

[Cellmer]

Funkcje wymagają udokumentowania, lecz ze względu na mało czasu do prezentacji daję approve'a, ponieważ funkcjonalność działa poprawnie.