Support for new The Handy APIv3 / firmware v4

[iwakan]

Over the past year, The Handy has been slowly rolling out their new APIv3 and accompanying firmware v4. This changes a lot of things over the previous API version, and I found that the current implementation in this software basically does not work at all with updated The Handy devices.

I roughly implemented a new output device for updated Handys in this PR: #217

[Yoooi0]

If each command has to go thru their servers does the firmware version even matter? I don't think the current implementation worked for anyone, so I don't see how support for new firmware would change it.
In MFP there would have to be a way to have something like PolledUpdate but with multiple script action buffering, so that you could send multiple moves with one command to The Handy. PolledUpdate assumes that the communication delay is small and consistent.

I think the better solution is to just wait for:
https://suggestions.handyfeeling.com/suggestions/595171/opensource-api-for-offline
Then we should be able to create our own local server for The Handy to connect to. This way the communication will be comparable to OSR.

Possible other solution: #164

[iwakan]

This firmware version makes all the difference in the world. I believe they redesigned the whole thing from the ground up, both the firmware and the new API to go with it. There are new modes in the API that isn't implemented in older firmware, and these modes are what makes live streaming of data possible, because they allow buffering multiple points, and that was in fact a major design goal of the firmware upgrade. The way MFP tries to handle it currently, sending points in real-time to the device, simply wasn't possible to do on earlier firmware, except locally over bluetooth. I figured out this the hard way with my work on the Teledong. The API modes that appeared to allow this functionality previously actually weren't designed for this use case, quoting the Handy team they were only designed for infrequent and rudimentary commands, not live transmission of actual motion like scripts, so the device response was way too slow and jagged to be usable.

Uploading scripts in advance as in #164 was possible on previous firmwares too, so that is a universal alternative, yes. But that's not the method MFP uses to send the data in the existing implementation so it would require more work to write.

Waiting for the offline API is also well and good, but the online API is something that works right now.