Allow empty arrays for SetChargePointListRequest / SetRoamingAuthorisationListRequest

[ahzf]

Requests like SetChargePointListRequest and SetRoamingAuthorisationListRequest expect at least one item in the request array, but this will inhibit any attempt to delete the entire list of charge points or roaming authorisations at the clearing house, which might be an important feature in some usecases. Therefore I would suggest to allow empty arrays whith the meaning of "delete all entries".

[simonschllng]

Originally, we specified it that way to prevent accidental deletes. This happened a few times during pilot phase. Another possibility is to add Delete...ListRequest methods to make full list deletes more explicit.

[ahzf]

Well, not having an explicit method to delete things is also bad when you want to scale up. Think of 1 million charging stations and you want to delete a single one - which might happen multiple times a day once someone operates such a big charging network. It would really be a total waste of transfer volume and CPU cycles to upload all stations every time again and again.

[mtdern]

In this case, you can markindividual EVSEs as "closed" explicitly using the Update-Method. A SetChargePointList missing that one EVSE in effect does the same thing. The same works for tokens.