* runservice: use generic task annotations instead of approval annotations
* runservice: add method to set task annotations
* gateway: when an user call the run task approval action, it will set in the
task annotations the approval users ids. The task won't be approved.
* scheduler: when the number of approvers meets the required minimum number
(currently 1) call the runservice to approve the task
In this way we could easily implement some approval features like requiring a
minimum number of approvers (saved in the task annotations) before marking the
run as approved in the runservice.
run changegroup names are based on the run path but it will contain slashes and
could be very long. So calculate the sha256 sum of the path and use it as the
changegroup name.
* Remove all the small index files on the lts
* Keep on s3 only a full index of all runs containing the runid, grouppath and phase
million of runs can take only some hundred of megabytes
* Periodically create a new dump of the index
