Update README.md

added mailing list etiquette link
Create What-is-the-mailing-list-nettiquete.md
Update What-is-the-mailing-list-nettiquete.md
Merge pull request #2 from wkitty42/master

added mailing list etiquette link to FAQ page, created new mailing list etiquette page, updated to fix typos and add clarifications