Add mapping value

[StefanoMartin]

It would be nice to have a way to create a mapping value easily.
At the moment we have something like this:

this.chargeLimit = await device.createNumberValue({
      name: 'charge_limit',
      permission: 'rw',
      type: 'mapping',
      min: 0,
      max: 2,
      unit: '',
      mapping: {"0": "action1", "1": "action2", "2": "action3"}
    })

I suggest to create something like this:

this.chargeLimit = await device.createMappingValue({
      name: 'charge_limit',
      permission: 'rw',
      mapping: ["action1", "action2", "action3"]
    })

Also the Wappsto UI should support this one instead of providing a slider.