Unless `token_text` is provided, will open a browser for two factor authentication.
Once logged in, retrieve the token from the user drop down in the upper right hand corner of the browser. Click the icon with the silhouette of a person, and select 'Copy API Token.' The token should be pasted into the popup prompt.
Arguments
- username
email address of sciencebase user. Will be retrieved from the `sb_user` environment variable if set. A prompt will be raised if not provided.
- token_text
character json formatted token text. `token_text` is stashed in R_user_dir and does not need to be re-entered unless it becomes stale.
If the token text is provided as input, no popup prompt will be raised.