[FEATURE] Refactor OIE, passwordless and standard widget signin methods

[mdwallick]

Currently there are 5 signin methods: hosted-widget, oie-widget, standard-widget, passwordless-widget and custom-widget. The oie, standard and passwordless signin methods need to be refactored into one method (new-standard-widget or something), with accompanying documentation on how to enable passwordless login, standard login, etc.

[mdwallick]

Additionally, it might be a good idea to also refactor each vertical such that at least the hosted and new OIE standard widget signin methods work.