Migrating pyside2 to pyside6 and making use of scikit-surgeryutils v2.0rc0

[mxochicale]

This issue will track the migration of pyside2 to pyside6 with the use of scikit-surgeryutils v2.0rc0

• 36 passed test in local ubuntu2204 machine (tox>py38OK,lintOK); refactors library with pyside6 dependency; fixs version requirements
• removes py3.7 due to end-of-life on 2023-06-27 https://devguide.python.org/versions/
• ci.yml: adds python versions 3.9, 3.10, 3.11, 3.12-dev
• adds python-version: 3.8 for python version for deploy
• Refactor ci.yml with linting, coverage and other missing bits for Qt for X11
• Remote unit test for python versions 3.9, 3.10, 3.11, 3.12-dev and ubuntu-latest, mac-latest and windows-latest has been sorted out
• Shall we use v1.0.2alpha? Steve mentioned that it is better to use the latest versions.
• Update main README
• update vtk/pyside2 to work with Python 3.8 #59
• Are we still pulling in opencv non headless? #109
• Stale branches #111

[mxochicale]

Unit test summary from https://github.com/SciKit-Surgery/scikit-surgerybard/actions/runs/4566120524

• Local machine ubuntu-22.04: 36 passed
• Remote ubuntu-22.04: 36 passed
• Remote mac-latests: 36 passed
• Remote windows-latests: 36 passed

[mxochicale]

• Create release candidate:

git checkout master
git pull origin master
git tag -a 'v1.0rc0' -m "Release candidate version v1.0rc0 using PySide6"
git push origin v1.0rc0 

• 🎉 release candidate 1.0rc0/ is available in pypi https://pypi.org/project/scikit-surgerybard/1.0rc0/ > https://pypi.org/project/scikit-surgerybard/#history