Per-user BOINC submission

[amereghe]

Prepare a crontab job listing all the users with work to be submitted. Then, call the present crontab job for submission, one instance per user, all users in parallel.
Locks should be per user.

[amereghe]

If HTBoinc enters into the games early enough, maybe we can skip this step

[amereghe]

HTBoinc will never enter into game.