Support for water valve with flood sensors

[klew]

We will use existing "valve open/close" funciton for valve.
Valve will be extended with "channel Flag" informing about config option to setup sensors.
Valve will gain "configuration" which will have up to 20 flood sensors (when flag is active).

Add binary sensor with new function "Flood sensor/Czunik zalania". There will be a new icon for it. Add support for all default functions, like reactions, etc.
Flood sensor: value 0 -> "no flood detected", 1 -> "Flood detected"

Apps will inform about: "flooding", "valve manually closed" flags. Additionally apps should aggregate info from linked sensors (new relation type). If some sensor is active, it should be shown on channel list.