Allow naming (and deleting) U2F devices.

What does this MR do?

• Allow giving each U2F device a name (at the time of registration).
• Allow deleting individual U2F devices.
• Display a list of registered U2F devices.

What are the relevant issue numbers?

• Closes #17334 (closed)
• Closes #17335 (closed)

Screenshots (if relevant)

Tasks

• #17334 (closed) !5833 (merged) Identifier for each U2F device
  • Implementation
  • Screenshots
  • Tests
  • CHANGELOG
  • Assign to miniboss
  • Assign to endboss
  • Wait for review/merge
  • Merge into EE and make sure there are no conflicts