Feature request: Give possibility to whitelist client object filter instead of just blacklist them

[pafade89]

Describe the idea
The filtering of the clients is currently possible, but only by exclusion and not to allow only individual clients for data input.

So it would be good if you can only get information's of desired clients and don't always have to pull all the data. Because even the exclusion is difficult in a network without a MAC address block, because you sometimes get unknown clients in the objects you do not wanted.

I create a pull request