Mention Application Settings wiki page in README
Mention Application Settings wiki page in README

There are many issues opened because users couldn't find information about settings in the wiki.

This changes the README.md to explicitly mention and link to the Application Settings wiki page. This is an alternative to PR #383 that moves the entire settings page into the readme.
brondavies/letsencrypt-win-simple,Lone-Coder/letsencrypt-win-simple