`watchdoc` requires manual token refresh

[TmLev]

watchdoc uses Gmail API, which is not available for service accounts, so it is done using the real email. That, in turn, requires manual authorization once a week, which is suboptimal at best.

• We could also store all applicant documents in the back-end instead of Google Drive.
• Maybe Own SMTP server or custom email service #265 will be of help.