Intermediate update 1.1.2

What's Changed

• Added missing mappings for MASVS V1.X.
• Updated markdown throughout the English MSTG to be consistent.
• Replaces some dead links.
• Improvements for rendering as a book, including the ISBN number.
• Updated the Excel: it is now available in Japanese as well!
• Many punctuation corrections, spelling and grammar issues resolved.
• Added missing iOS test case regarding memory corruption issues.
• Added contributing, code of conduct, markdown linting and dead link detection.