Store creation M1: WordPress.com account creation

[jaclync]

Previously, we were going to use the UX in the WP apps for WPCOM account creation #7793. Some work on the Networking and Yosemite layer was done, but we decided to go with a new UX that is more consistent with the web.

For #7879
Project thread (store creation): pe5sF9-I3-p2
Design: HyVloP5FipZzyPVenH2euI-fi-1262%3A61690

Subtasks

Networking layer

• Add necessary endpoints to AccountRemoteProtocol and implement them in AccountRemote Store creation MVP - account creation: networking layer changes #7897
  • Load user name suggestions
  • Create an account

Yosemite layer

There’s no need to persist any of the results.

• Add the following cases to AccountCreationAction enum similar to the networking layer Store creation MVP - account creation: Yosemite layer changes #7898

App layer

• Create a new screen AccountCreationForm and its view model AccountCreationFormViewModel to display the email and password fields Store creation MVP - account creation: form UI #7906
• Add a CTA to log in for existing users Account creation: add login CTA for existing users #7952
• Navigate to the store creation flow after a WPCOM account is created & auth token is received Store creation MVP: add entry point to prologue after account creation #7927

Issues

• Handle username error by generating another username with some base string (Account creation: add login CTA for existing users #7952 (comment) p1666852701302039-slack-C045CUK1Y3U) Account creation: handle email-based username error by generating another fallback username #7986

Design polishes

• Update font styles to match design Account creation: design polishes - fonts, ToS link, text field focus styles #7995
• Can we enhance the text fields a bit: hide the default borders and add custom ones 10pt from the content; the color can be highlighted based on @focusstate. (ref) Account creation: design polishes - fonts, ToS link, text field focus styles #7995
• Should we show an in-app browser for the ToS link instead of opening Safari? We can use SafariView for that. My idea is that it's better to keep users within the app than to send them somewhere else (ref) Account creation: design polishes - fonts, ToS link, text field focus styles #7995
• Update Terms of Service link to underline in AttributedText, refactoring is required where the link underline color is set to clear (though it doesn't match other use cases in the app like IPP learn more) Account creation: design polishes - update ToS link style to an underline, font/color updates #8007
• Add the eye icon to the password field to show the password Account creation: design polishes - add a button to show/hide text field input for a secure field #8006

Tech debt

• A better way to support unauthenticated AlamofireNetwork Store creation MVP - account creation: Yosemite layer changes #7898 (comment) Account creation: add UnauthenticatedRequest instead of passing empty credentials to AuthenticatedRequest #8029
• Unit tests for AccountCreationFormViewModel Add unit tests for AccountCreationFormViewModel #8024