If a bounty is created for a specific user, send that user a message after bounty is created

[tescher]

assignTo is set in the Create activity, but no message goes out to the user so they don't know it.

[tescher]

To Do:

• In Create actvity, remove setting of assignTo, and create an AssignRequest.
• In AssignRequest, handle a request without a commandContext, i.e a directRequest context
• Create a attemptDM routine, which attempts to send a DM with content, creates a message in the Bounty Channel if it can't. Start replacing user.send with that.
• In ActivityResponse call this if no context, and ActivityNotification,call this instead of the user.send.
• Get rid of NotificationPermissionError and its usage