Add top entities to Console sidebar

[kschiffer]

Summary

As per the redesign plans, we want to feature top entities in the sidebar.

Current Situation

No such thing in the Console. Entities can only be navigated by the regular entity lists.

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

To improve access to frequently used entities without having to find them in the list of all entities only.

Proposed Implementation

Design can be found here: https://www.figma.com/file/7pBLWK4tsjoAbyJq2viMAQ/console-redesign?type=design&node-id=1293-8589&mode=design&t=KahtD0FTWntVj2IO-4

As laid out in #6937, the concept of "Top entities" still needs to be flashed out, but for the time being, we can just use bookmarks here. As such, #6936 needs to be implemented first.

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.