Allow override of scrollViewDidScroll in CardsViewController

[jmjordan]

Is your feature request related to a problem? Please describe.
I would like to be able to override scrollViewDidScroll in a CardsViewController for custom UI

Describe the solution you'd like
Change scrollViewDidScroll in CardsViewController to open

Describe alternatives you've considered
A custom delegate method could be created but I don't think that's necessary

Additional context
None

[jmjordan]

I'm happy to do the work if it is approved.

[badrinathvm]

@jmjordan Please send us PR we will review and take it further. Thank you.

[jmjordan]

PR submitted: #247