Update package layout to PyAnsys guidelines

[jorgepiloto]

As with other projects in the PyAnsys ecosystem, the layout of this project should adapt to the general guidelines.

Low effort

• Enable Ruff rules

  • PyCodestyle
  • PyDocstyle, see doc: pydocstyle ruff rule #1975
  • PyFlakes, see fix: pyflakes style #1953
  • Isort, see feat: enable isort ruff rule #2021
  • PEP8-Naming
  • Flake9-use-pathlib, see maint: modifying files to conform with "PTH" ruff rule #1949
  • Flake8-todos, see Doc: flake8 todos #1981

• Remove autoapi warning suppression once the codebase is healthier. See Address api documentation generation warning suppressions #1967

• Address removed reference labels from module docstrings. See Fix potentially broken references in the documentation #1980

Intermediate effort

• Use a src/ layout. Just need to move the "ansys/" dir inside a "src/" one and fix some links to this new location: Use src/ dir #664

• Use a pyproject.toml and drop any setup.py or setup.cfg files. Simplify library installation #909

• Rename /docs directory to /doc: Link issue here.

• Implement Tox for the project

  • Drop any patch scripts in favor of Tox
    • Feat: tox implementation #1989
    • feat: add documentation build environment to tox.ini #2015
    • ci: use tox in ci #2031
    • ci: parallelize some tests #2056

• Use sphinx-autoapi for generating the API reference, see doc: use sphinx-autoapi for API reference #1952

• Improve static search live preview performance and fix missing module icons in the api documentation, see Doc: improve static search speed and fix missing module icons #1971

High effort

• Use containers from the GitHub Container Registry in the CI/CD
• Rename master branch to main
• Use semver tags

More about packaging guidelines in https://dev.docs.pyansys.com/packaging/structure.html.