Improve detailed mapathon stats

[NicolasGrosjean]

Is your feature request related to a problem? Please describe.

• In addition of spent time too big ([BUG] Tasking Manager validation time too big #327), there are a lot of side effects depending the chosen timestamps (see additional context).

Describe the solution you'd like

A propose to write a clear definition of all statistics and update the needed ones (for example compute spent time with intersect the input timestamps).

It could be good to displays later these definitions in the UI.

Describe alternatives you've considered

Add a lot of warnings about displayed spent time outside the input timestamps, non displayed spent time, ...

The API should return these warnings and the UI should display them.

Additional context

Example of the issues

Between 4:15PM and 4:30PM we see no data:

Between 4:30PM and 4:45PM we see building data but N/A for TM data

Between 4:15PM and 4:45PM we see in addition to building data 51,770 seconds of validation (more than 14 hours but it is in fact the validation of 10 tasks in 1h26min17s).