Implement user preference store integration for the Console

[kschiffer]

Summary

As per the redesign plan, we are adding a feature that allows users to store preferences such as bookmarked entities, dashboard layout, dark mode, and sort orders.
The backend work for this can be tracked in #6890 and we can already work on adding these services to the SDK and Console store logic.

Current Situation

There is currently no way for users to store any of these things.

Why do we need this? Who uses it, and when?

To allow for customization and personalization of the Console. Especially bookmarks will assist users to access frequently used entities.

Proposed Implementation

This should be pretty straightforward CRUD plumbing. For the current designs, we'd only need to create, delete and list bookmarks. But I think it's good to add the store logic for the remaining preferences as well (dark mode, sort orders, dashboard layout).
The current designs use only bookmarks for now, these will be used in the Sidebar, the Top Entities Panel and the Bookmark button in the header.

Contributing

• I can help by doing more research.
• I can help by implementing the feature after the proposal above is approved.
• I can help by testing the feature before it's released.

Code of Conduct

• I agree to follow TTN's Community Code of Conduct.