feat: Add support for Customer & Payments sessions, thus enabling one to use the SDK UI kit

[andreibarabas]

Currently, you need to build the entire UI yourself, but with the support for ephemeral keys, customer and payment sessions, you can now leverage the SDK UI kit available. Read more at Android Basic Integration

@viktorasl - the PR is based upon the other open one #8 so we should probably get that merged first and then rebase it off of it, but just wanted to bring this into discussion.

Currently it works only on Android, but since you are more versatile in iOS dev, maybe you can solve that part?

[andreibarabas]

hey @lukebrandonfarrell , @viktorasl - what do you guys think? is this something you want in the library?

[lukebrandonfarrell]

I'd want this in the library for sure. Will be able to have a proper review of this end of week. Let's see what @viktorasl thinks

[viktorasl]

Um, yeah, we should sort out previous MR and then we'll jump on this one! Anyways, thanks for the contribution!

[andreibarabas]

Sure guys. I'm already testing it in production, so let me know when you guys finished with the previous one to rebase it and have it merged.

[andreferi3]

any updates ?

[andreibarabas]

@andreferi3 - we've been using this PR in production for quite a while now, so while there is no update on the merge, feel free to use it

[rawatnaresh]

@andreibarabas I'm getting Error: There was an unexpected error -- try again in a few seconds while using this branch. although the master branch is working as expected. also, the types for billingDetails are missing on theconfirmSetup