support specifiying b2c policy used when generating the login button see issue

[richardjharding]

This change adds the option to supply a B2C policy name in the options - this is then used when generating the button url for users to click when signing in

see #22

[mattdot]

Thanks for submitting a pull request. I'm not going to merge it right now because I want to look at other options for supporting this which don't require putting the b2c option on an interface that other providers have to implement. I do really appreciate you taking the initiative to fix the issue and submit a fix though.

[richardjharding]

no problem it was just something I needed for a project - do you have an idea when this will be supported in the published npm?

[tschnoelzer]

Hi Team,

are there any plans to provide a AD B2C nodejs sample? we are really struggeling and love to implement the bot with B2C provider.

Any clue warmly welcomed!

Best

Timo