Add race start time as datetime timestamp attribute

[skulumani]

It would be useful to add the datetime time for start of each race as an additional attribute.

I'll try to take a look through your code and how you build it and submit a PR.

Thanks!

[skulumani]

Looks like the atrributes are built here

And it's actually just copying the data from the ergast API into the attributes dictionary. I guess the dictionary would have to change then