Add Sphinx documentation and Read the Docs config

[camUrban]

Introduces a full documentation site for PteraSoftware using Sphinx, including configuration files, custom templates, static assets, and example content. Adds .readthedocs.yaml for Read the Docs integration and updates IDE settings for a dedicated docs virtual environment.

Description

Adds documentation hosted by Read the Docs.

Motivation

Hopefully this will make getting started with Ptera Software more accessible.

Relevant Issues

Closes #57

Changes

• Added new dependencies to docs\requirements_docs.txt
• Added directories docs\_static, docs\_templates, docs\favicons, and docs\internals for storing assets for the documentation website
• Added files .readthedocs.yaml, docs\api.md, docs\conf.py, docs\examples.md, docs\index.md, docs\install.md docs\internals.md, and docs\quickstart.md to configure the website
• Added the auto-generated documentation content in docs/_build/ to the .gitignore

New Dependencies

Development Dependencies

• furo
• myst-parser
• sphinx
• sphinx-autoapi
• sphinx-copybutton

Change Magnitude

Minor: Small change such as a bug fix, small enhancement, or documentation update.

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Checklist

• [x] I have created or claimed an issue for this work as described in Contributing Code.
• [ ] My branch is based on main and is up to date with the upstream main branch.
• [x] All calculations use S.I. units.
• [x] Code is formatted with black (line length = 88).
• [ ] Code is well documented with block comments where appropriate.
• [x] Any external code, algorithms, or equations used have been cited in comments or docstrings.
• [ ] All new modules, classes, functions, and methods have docstrings in reStructuredText format, and are formatted using docformatter (--in-place --black).
• [ ] All new classes, functions, and methods use type hints.
• [x] If any major functionality was added or significantly changed, I have added or updated tests in the tests package.
• [x] Code locally passes all tests in the tests package.
• [ ] After pushing, PR passes all automated checks (codespell, black, mypy, and tests).
• [x] PR description links all relevant issues and follows this template.

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