Remember my Choice for this Service feature in WAYF

With the introduction and increasing adoption of eduID there will be more and more services who will enable eduID as a means to login. Many (of those) services however currently have only 1 IdP connected, namely the institution for which this service is meant. With 1 IdP, the WAYF is skipped. So enabling eduID will lead to extra clicks for all users. This is expected to be a problem by at least 1 institution / use case.

EB already has a 'remember my choice' feature, but in SURFconext it's currently disabled. The main reason is a) until now, there hasn't been a need to enable it and b) the design is not suited to show to users. Also c) it's lacking some functionality (see below).

After careful deliberation, the following steps are needed:

1. Make a new design (done)
2. Add metadata option to Manage to be able to enable "remember WAYF" per SP
3. Implement "remember my choice for this service" in Engineblock (feature-flagged so admins can choose between disabled, global or per-SP "remember my choice" functionality)
4. Enhance OpenConext Profile with a feature so users can reset "remember this choice" settings
5. Document this feature in the public (SURFconext) documentation

[!NOTE]
Further elaboration fo this ticket has been moved to the subtickets.

Start by reviewing the subtickets referenced in the issue and the existing Engineblock “remember my choice” feature. Trace the Manage metadata path, Engineblock feature-flag behavior, OpenConext Profile reset functionality, and public documentation requirements. Done means the requested per-SP configuration, selectable behavior, user reset option, and documentation are all covered.