code moves for reusability

1. Moving the config and appname getters to the main class for reusability.
  1. Sadly, the browser monitoring doesn't allow setting the app name by plain text (it has to be pre-registered in the NR dashboard), and there really isn't any use for the config method except in APM yet, but this is the right direction to go overall.
1. I also moved the Browser monitoring UI to the Settings tab, instead of Plugins. That's a critical change for some environments.
1. Moved/renamed readme (and updated deploy script) so it renders in github and can be easily transformed to the WP.org plugin repo markdown standard.
1. Incremented version number to reflect addition of browser-only monitoring.

Mostly relevant to https://github.com/GigaOM/gigaom/issues/5525