allow config / functionality for dockless scheme

[nekromoff]

Use case:

• dockless bikesharing system

Scenario: Rent and return of bikes possible without any stands.

1. User leaves / returns bicycle, system takes the GPS location and saves it on a map.
2. Next user can see bicycles on a map (instead of stands) and find the closest one.
3. User comes, sees bicycle, rents it via system using ordinary code/new code cycle.
4. User returns bicycle and locks it using the new code, system takes the GPS location and saves it.

[ewooonk]

relevant: #94