simplify the initial configuration by automatically fetching the token

[scelfo]

The configuration page requires a "BOND Hub Token" value. This token is actually available with an unauthenticated request, it's presumably used to protect against cross site request forgery.

Reading through http://docs-local.appbond.com/#section/Getting-Started/Getting-the-Bond-Token it should be possible to simplify the initial configuration by fetching the token every time hubitat polls bond.