Add alternative to Optic mobile app for NPM publishing

[simoneb]

It would be good to have alternative ways to generate NPM OTPs in addition to the mobile app.

One way might be to use something like https://github.com/boasiHQ/interactive-inputs, which allows providing inputs during the execution of the workflow. We could set up a page that, when navigated to, accepts a OTP that the user will provide and that the action will use to publish to NPM.

I believe setting this up would be quite easy, it's mostly a matter of deciding how to design the API, which basically means modeling the action inputs, that the user will configure to decide whether to use the Optic app or the alternative way.

We could even consider making them work together at the same time, when configured. E.g. we will both try to send a push notification to the app, AND set up a page via the interactive inputs action. Whatever returns an OTP first, we'll use it!

[simoneb]

@msgadi