Restructuring of Documentation

Main changes include restructuring of the /docs folder, specifically:

• Documentation has been moved to /docs/docsrc folder in order to enable use of /docs for GitHub Pages.
• ReadTheDocs configuration file .readthedocs.yaml has been introduced. It points ReadTheDocs to /docs/docsrc/source/conf.py file for configurations.
• Sphinx method make github has been introduced in order to generate the documentation on the /docs/docsrc/build and then copy-paste it to /docs for GitHub Pages.