Add option to hook "createUserWithEmailAndPassword" for enabling email verification sendout

[dohomi]

I added an option to send out the email verification after successful creation.
Let me know what you think about this.

[chrisbianca]

Thanks @dohomi, this is a nice addition to the functionality. I'll get some documentation added and a new release shortly

[dohomi]

@chrisbianca I kind of overlooked that the function takes props for example to set a redirect URL (which most likely everybody sets to redirect back to the application)

user.sendEmailVerification(options: firebase.auth.ActionCodeSettings)

I can open a second PR to pass this options in as well

[chrisbianca]

Thanks @dohomi, both have been released in https://github.com/CSFrequency/react-firebase-hooks/releases/tag/v3.0.3