refactor initialize_world.py to be more concise

[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

13 tests  ±0   13 ✔️ ±0   2s ⏱️ -1s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit 6a7d6a8. ± Comparison against base commit af1146f.

♻️ This comment has been updated with latest results.

[Cellmer]

LGTM jak to mówią

[Cellmer]

ewentualnie można zmienić nazwę pull requesta i udokumentować funkcję add_entity choć nie było to akurat zadaniem tego konkretnego pull requesta