Add integration of non-digital VI's

[gigatexel]

This code aims to integrate VI's that are configured as being non-digital.

VI's configured this way, enable easy transfer of numerical data from HA to Loxone (and vice-versa). The code implements this using Number-entities and considers the min, max and step parameters in Loxone.

The type of Number is determined by Home Assistant.

In my use case, I use this to:

• Send P1 digital meter data to Loxone, since Loxone has no supported P1 interface. HA does, using the DSMR integration
• Get the level of the rainwater storage tank. This is a very noisy signal, and H1 does a great job filtering this. The filtered value is then sent to Loxone.

[JoDehli]

@gigatexel I merged it by hand. I did not test it because I do not use VI. Thanks for your work.