refactor: Combine the storage interface for storage and pkce in gotrue_client

[Vinzent03]

What kind of change does this PR introduce?

refactor

What is the current behavior?

The session gets stored by the supabase_flutter package by listening to auth events. The session is stored in a different place than the pkce token.

What is the new behavior?

The gotrue package manages the session storage itself (like in supabase-js) and uses the same interface as the pkce token.

Reasons for this pr:

• Have a more similar approach to saving the session like in supabase-js
• Make it less confusing for the user to have to provide two different storage interfaces to customize the storage of the session and the pkce token
• Provide a built-in interface to persist the session if not using supabase_flutter
• The auth client has now the persistSession field, which is now used to explicitly turn on the session broadcasting. close Version 2.7.0 prevents reading data on web under certain conditions #1085

I deprecated both localStorage (used for session storage by supabase_flutter) and pkceAsyncStorage (used by supabase to store the pkce token) and replace them with a unified storage interface asyncStorage, which uses the GotrueAsyncStorage class, which was previsouly used for pkce only. To support existing configuration I created a new class, which combines both deprecated interfaces into one and decides by the suffix of the storage key to use the session storage or pkce storage.

Additionally, I noticed that many document comments were outdated, because of the 'new' options classes for each package, so I updated them.

Additional context

[dshukertjr]

Thanks for this PR, but honestly, I am not a huge fan of these refactorings. I feel like the library is deviating more and more from supabase-js, which makes it hard to maintain. Unless there is something broken, I'd say we keep it the way it is, and maybe we can revisit it when a major version release comes.

[Vinzent03]

I'm quite confused, because the whole goal of this pr is to align with supabase-js .

• This now uses a single storage interface like supabase-js -> session and pkce are no longer handled separately like it's done in supabase-js
• This now uses the same storage interface like supabase-js
• The session is stored by the auth client itself like in auth-js instead of having to listen to the onAuthStateChange stream in supabase_flutter.
• The session is only broadcasted if the session is persisted, just like in auth-js

So this pr makes it easier to maintain the similarity to the js sdk.
Example:
Beforehand it was not possible to disable the session broadcasting like in auth-js, which I already mentioned in that pr, because the sdk were deviated. But with these changes it's implemented like in supabase-js

[dshukertjr]

It's a refactoring that doesn't really solve any issues that users are asking for. We can probably wait for a major version bump for changes like this.