Add VR600 Support

[GuyKh]

Solves #2

[GuyKh]

Don't merge yet.

As a script this works but I want to test it in HA

[ericpignet]

Thanks for the contribution!
I let you test in HA, let me know when it's ready!

[GuyKh]

@ericpignet

2020-05-06 10:36:01 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Retrieving PublicKey...
2020-05-06 10:36:01 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Failed to get AuthTokens. Retrying in 3 secs.
2020-05-06 10:36:04 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Retrieving PublicKey...
2020-05-06 10:36:04 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Retrieving JSessionID...
2020-05-06 10:36:05 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Retrieving Token...
2020-05-06 10:36:05 INFO (SyncWorker_19) [custom_components.tplink_router.device_tracker] Loading wireless clients...`

Looks great!

[ericpignet]

Well done, thanks for the contribution!
Is pull request ready to merge?
(looks good but I'll give it a try anyway, just to check Tplink6DeviceScannerit doesn't fail abruptly, preventing other scanners to be tried)

[GuyKh]

@ericpignet on my end - yes.
Here and there I see that 192.168.1.1 times out - but that's not in the initialization step.
So I'm kinda comfortable with merging this

[ericpignet]

There were a few formatting issues: inconsistent indentation (2 chars), trailing whitespaces, double new lines. But that's alright, I'm planning to do an update shortly to clean up the logging, I'll take the opportunity to reformat.
I'm merging your PR.
Thanks again!

[GuyKh]

@ericpignet - thanks for your notes.
For some reason I didn't see this when comitting, but I'll put extra attention to it.

Thanks again