552 implement adding sub scenes in the scene editor

[teres4]

Closes #552, #1056

Description

Include a summary of the changes here.

Checklist

• [ ] Self-review changes.
• [ ] Evaluate impact on the documentation.
• [ ] Ensure test coverage.
• [ ] Write new samples.
• [ ] Add entry to the changelog's unreleased section.

[github-actions[bot]]

PR Preview Action v1.4.7 :---: :rocket: Deployed preview to https://GameDevTecnico.github.io/cubos/docs-preview/pr-1122/ on branch gh-pages at 2024-05-07 19:40 UTC

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 0% with 11 lines in your changes are missing coverage. Please review.

Project coverage is 39.09%. Comparing base (2800631) to head (256f585).

Files	Patch %	Lines
engine/src/assets/assets.cpp	0.00%	11 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1122 +/- ## ========================================== - Coverage 39.10% 39.09% -0.02% ========================================== Files 359 359 Lines 26647 26655 +8 ========================================== Hits 10421 10421 - Misses 16226 16234 +8 ```

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