MNT: Encapsulate quaternion conversions

[Gui-FernandesBR]

Pull request type

• Code maintenance (refactoring, formatting, tests)

Checklist

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

Current behavior

We take quaternions (euler parameters) and calculate euler angles inside the flight class, but this code cannot be reused in other applications.

New behavior

• The quaternions -> angles conversions were moved to the tools.py module, thus allowing for other classes to access these functions.
• The Flight class was adjusted to use the new functions.

Breaking change

• No (I'm not sure if we should create a new .py file just to put these functions or not.)

Additional information

This is going to be quite useful for the rocketpy.simulation.FlightDataImporter class.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (08d3a42) 72.32% compared to head (b55fdd2) 72.34%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #537      +/-   ##
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+ Coverage    72.32%   72.34%   +0.01%     
===========================================
  Files           56       56              
  Lines         9389     9393       +4     
===========================================
+ Hits          6791     6795       +4     
  Misses        2598     2598              

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[phmbressan]

The documentation helps, but I have a minor issue with the naming schema of the created functions.

You certainly have more experience on quaternions than I, so I would like to hear your opinion:

• Except the precession one, the names end up with the angle naming convention used for RocketPy (phi, theta).

• I know this is a common angle convention, but I am not sure of it is universal. So I believe it would be better to name them after their "physical angle", such as precession and nutation.

[Gui-FernandesBR]

The documentation helps, but I have a minor issue with the naming schema of the created functions.

You certainly have more experience on quaternions than I, so I would like to hear your opinion:

• Except the precession one, the names end up with the angle naming convention used for RocketPy (phi, theta).
• I know this is a common angle convention, but I am not sure of it is universal. So I believe it would be better to name them after their "physical angle", such as precession and nutation.

You have a good point.
I solved that with the cdb42ec.

Can you please re-review it?