Issues with helpers: Generator

[EzzatElmo]

The Generator (python/petsird/helpers/Generator.py) does not use the parameter "NUMBER_OF_EVENTS"
It is defined but not used within the code. So to change the amount of events you need to change the rate.

But since we have the time information and the events information, it seems like the rate should be calculated instead of being hardcoded.

[KrisThielemans]

Ok to just remove NUMBER_OF_EVENTS? It currently generates it (randomly)