v5.0.0-rc.0 switch from request to axios

Since the request package is no longer receiving updates, wait-on switched to using axios. Attempt to keep the same wait-on options as much as possible.

These breaking changes occurred in the switch:

1. There is only one option for redirects followRedirect: true|false (defaults to true).
2. httpSignature is not implemented in axios and now not available. (If this feature is still desired, please help by providing a pull request to implement it.)
3. auth allows only username and password but not the previous aliases user and pass