- Implement RotateSecret to support initial setup of secret rotation.
Moto's implementation of secrets is currently flat and needs to gain
some dimension before full rotation can be simulated.
- Add the happy path unit test.
- Save friendly name in create_secret.
- Reference the saved friendly name in responses that have "Name" field.
- Verify the received secret_id matches the current value. Don't just
test for an empty string.
- Add test for mismatched secret_id.