[ideAlarm] - Allow arming/disarming through number item

[Mr-Eskildsen]

As I would like some kind of automated arming of some of my zones, I find the approach with two switches makes it difficult to change the value, eg. if it is already armed, it will get disarmed.

Additional to the switches I will suggest a Numeric item that can hold the requested arming mode (0, 1 or 2) and then directly ensure that the relevant mode will be set (without disarming). This would make it much easier to maintain from rules.

For backward compability I suggest to keep the buttons.
I will work on a suggestion. Comments regarding pros and cons for functionality are welcome