Change library name to BrazilCEP

• Rename lib to BrazilCEP
• Create new pip package
• Remove support for Python 3.5, 3.6, and 3.7
• Add support to Python 3.9, 3.10, and 3.11
• Add poetry to manage project dependencies
• Add matrix test of Python versions using nox
• Improve docs and code
• Fix Github actions lint
• Fix Github actions coverage
• Improve lint test
• Improve coverage test
• Create docs site (translate to English)
• Update contribute doc to use poetry