This reverts commit d57eb0721b.

We can use raw value as-is. While the lack of unit is true for the value represented as cos θ , we don't specifically have any other sensors using it as such. As comment suggest (huh), we want to express the thing as a percentage.

* Update PZEM004TV30Sensor.h

See table above for the correct scale

* Power factor has no unit

Add new V3.0 version of PZEM004T, not tested. Default to factory default address 0xf8, configurable through pzemv30Addr 8-bit number
Add 'frequency' measurement & 'hz' unit
Add pz.address that configures address
Implemented energy reset

Right now we only support a single device. No way to test this properly (mostly, how exactly we need to connect this stuff), so left as not implemented.