Make a login view

[alexmodrono]

• I know that I'm requesting a feature for Codename Starlight (SwiftUI) and not for Hyperspace Desktop (JS).

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We can't work with private user data, such as Notifications, Home timelines, suggestions, etc.

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We've already done a Network view where users can see the public and local timeline, but we need to start working with private data.

For that reason, we need to implement a login view so that we can obtain a user token.

[alicerunsonfedora]

We should have some of the logic implemented in AppClient as well since we have the setup for both the base URL and the token. We should be able to use a developer token for the time being so that we can test things before we work on the authentication process. Not sure if we'll need to set up Sign In with Apple, though... 🤔

[alicerunsonfedora]

Started adding a UI mockup for the login screen with an access token-based alternative if the normal means isn't working.

[alicerunsonfedora]

Update: @iAlex11 is working on implementing the new login design from Discord