Add `IServiceProvider` access when registering scheduled job

[stijnmoreels]

Describe the feature you would like to have:
Currently, a scheduled job can be added without any IServiceProvider access. This can be rather tedious as when registering an UnobservedTaskExceptionHandler, one might want to use the registered ILogger<> instead.
In the sample app in this repo, we see the same problem recurring.

A possible way, is to add an overload that takes in Action<SchedulerBuilder, IServiceProvider> or something like that, so the configuration can access the IServiceProvider and the registered services.

File to change

[kdcllc]

@stijnmoreels I am sorry for the delay in merging your changes. I completed your changes here #50

[stijnmoreels]

@stijnmoreels I am sorry for the delay in merging your changes. I completed your changes here #50

Oh, that's great! 🥳
Thx!
Hope it helps people when managing their scheduled jobs.