Upgrade to API V2

[urkle]

We need to get this tool updated to use our V2 API and personal access tokens.

To do that we need to have the following

1. the "authentication" action needs to be removed and replaced with an action that accepts a personal refresh token.
   a) that action should contact our authentication server to obtain an access token( see https://developer.hubstaff.com/authentication#pat )
   b) it should then persist (where the token was saved before) the access token, refresh token, and expire time (convert the expires_in to an actual timestamp/unix seconds)
2. the API access code needs to be adjusted to utilize the access token instead now and each call should first verify that the token is not yet expired (if expire time is < 5 minutes from now refresh it and persist that new data)
3. the endpoints calls need to be updated to their V2 counterparts.