[datetime] Time-series display actual time

[Edouard2laire]

This is the first POC for showing the actual time of the recording.

Most of the other time are not changed. Should it be converted to time too ?

The events for example:

I think it's not necessary. what do you think ?

When we display a raw signal; and an imported signal, do we want to change the x-axis to hours for both figure ? Example: