Prompt for password and cache `cloud.session.token`

[bwbaugh]

Feature request to avoid having to store a password on disk if desired.

This utility’s approach might be a good example:

https://github.com/Netflix-Skunkworks/go-jira/blob/9a62d1a5530640fb8c5824e31de136dbc1829937/README.md#authentication

[bartfrenk]

Thanks!