Follow-up: provide 3-sphere with additional features

[gh-mjungmath]

This is a follow-up of #30804. This ticket provides:

• a Lie group structure of S^{3 (?)}
• a global frame of S³
• Hopf coordinates

[mkoeppe]

Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review.

[egourgoulhon]

Just a reminder of some notebooks which might serve as starting points for this project:

• Hopf coordinates: ​https://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Notebooks/SM_sphere_S3_Hopf.ipynb
• Lie group structure: ​https://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Notebooks/SM_sphere_S3_vectors.ipynb
• Riemannian structure: ​https://nbviewer.jupyter.org/github/sagemanifolds/SageManifolds/blob/master/Notebooks/SM_sphere_S3_metric.ipynb

[egourgoulhon]

Also, regarding Lie groups in Sage, at the moment, we have only nilpotent Lie groups (cf. ​https://doc.sagemath.org/html/en/reference/groups/sage/groups/lie_gps/nilpotent_lie_group.html), which have been implemented through ​https://trac.sagemath.org/ticket/26344.