Clean up capabilities and data processing for v2 devices

[DCSBL]

This was a bit of a rabbit hole so this ended up being a big change... But I am pretty confident that there are no breaking changes, we even got some extra sensors.

• For battery, moved creation of capabilities to init to reduce a tiny bit of the load during polling
• For P1 Meter I started to do the same, but I forgot that every smart meter provides different data. So I've ended up cleaning up the implementation. I think it performs the same (or worse), but it feels a bit more maintain friendly.
  • I left the 'external' alone for now
  • I don't think we need that flow trigger thingy, but I implemented because I don't know if/how it is used
  • Implemented all tariffs, and found that data.total_power_import_t3_kwh was still the 'old' JSON name. Fixed that.

"Works on my machine", so please please let users know things can break.

[DCSBL]

Thanks! Please let me know if users have any feedback. I am done for today 💤

[jtebbens]

Awesome job!

[jtebbens]

Energy_v2: Found some meter_power.consumed / produced t4 that were in the device code but not in the driver.compose.json (fixed)