ENH: Exponential backoff decorator (fix #449)

[Gui-FernandesBR]

Pull request type

• [x] Code changes (bugfix, features)

Checklist

• [x] Tests for the changes have been added (if needed)
• [x] Docs have been reviewed and added / updated
• [x] Lint (black rocketpy/ tests/) has passed locally
• [x] All tests (pytest tests -m slow --runslow) have passed locally
• [x] CHANGELOG.md has been updated (if relevant)

Current behavior

It is annoying that several tests fail due to bad approach of fetching external APIs data.

New behavior

Fixed the issue #449 . Code is running ok, I also testes slow tests.

Breaking change

• [x] No

Additional information

I was really tired of seeing the Wyoming atmosphere model failing in our tests.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 39.36170% with 57 lines in your changes are missing coverage. Please review.

Project coverage is 72.93%. Comparing base (6b26f61) to head (b899064). Report is 1 commits behind head on develop.

Files	Patch %	Lines
rocketpy/environment/environment.py	27.27%	56 Missing :warning:
rocketpy/tools.py	94.11%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #588 +/- ## =========================================== + Coverage 72.88% 72.93% +0.05% =========================================== Files 59 59 Lines 9591 9628 +37 =========================================== + Hits 6990 7022 +32 - Misses 2601 2606 +5 ```

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