Cookie Renewal for SBL cookie

[TheTechArch]

Description
When a user is logged in to Altinn and access Altinn Apps / Altinn Platform the forms authentication cookie (.aspxauth) used in the old platform will not be refreshed.

A user can experience that he is logged out when he redirects back to messagebox even he has been active all the time.

To prevent this SBL needs to authenticate the forms authentication cookie based on the altinnstudioruntime cookie.

The Altinn Studio runtimecookie contains a JWT token. That token will be refreshed while user is using Altinn Apps or Altinn Platform.

The proposed solutions it that when a user is redirected to login page in SBL portal, that SBL page needs to verify if there exist a valid JWT cookie and if so generate a new .aspxauth cookie based on the claims in the JWT token.

We need to create a mechanismen to update the SBL cookie when the JWTCookie is refreshed/created and update through the JWTCookie refresh endpoint #1718

Acceptance criterea

• A user gets his forms authentication cookie updated when using Altinn Apps / Platform

[lvbachmann]

@acn-sbuad Do you know any remaining work left to achieve the goals of this epic when #3927 is complete? If not - we'll mark this as done.

[lvbachmann]

All issues closed, thus closing the epic.