Monitoring service

This is the recollection of requirements defined the 29th of April 2014 in Barcelona, as a prioritized users story list (lowest value = highest priority):

1. AS Administrator I WANT/NEED TO free the accounting from WMSHistory
2. AS Shifter I WANT/NEED TO see how many jobs/pilots are in a transient state, now, and in the recent history
3. AS Shifter I WANT/NEED TO make the previous selections/display based on the jobs/pilots attributes as metrics
4. AS Shifter I WANT/NEED TO see the rate of jobs/pilots entering in any state in the recent history
5. AS Shifter I WANT/NEED TO define arbitrary precision for all the monitoring plots
6. AS Shifter I WANT/NEED TO define arbitrary the time window of the monitoring plots
7. AS Administrator I WANT/NEED TO free the accounting from recorded info that are considered useless
8. AS VO I WANT/NEED TO add metrics
9. AS Shifter I WANT/NEED TO be notified of certain events

For the highest priority user story we need the development in https://github.com/DIRACGrid/DIRAC/wiki/Monitoring-service followed by operation actions.