Quaternions are used incorrectly

[Nielsbishere]

Is your design request related to a problem? Please describe.
The current implementation of parenting only uses euler angles that get converted to quaternions and then to matrices. This is correct, but doesn't make any sense. It would be better to convert "all" matrices to quaternions; reducing the memory/bandwidth cost and increasing performance.

Describe the solution you'd like
Only use matrices when needed (like clip space conversions) and use quaternions otherwise.

Describe alternatives you've considered
Matrices can still be used, but will result into rotations being less accurate and potential rendering issues.

Additional context
N.A.

[VZout]

Currently we also have a used_quaternion boolean. This is quite a bad way to handle quaternions. Requires a better version in the future.