Add config/mode support for ubisys device C4 (5504)

[jensflorian]

Does the issue really belong here?

• I definitively want to report a bug within deCONZ or its REST-API

Is there already an existing issue for this?

• I have searched the existing issues and there is none for the bug at hand

Describe the bug

Similiar to other ubisys devices ( see #7459) the C4 technically supports configuration of the button modes as "momentary" or "rocker" types.

Because the C4 has four endpoints, the command is slightly different from S1 / S2 devices. Default configuration is shown on page 30 of the device reference manual: https://www.ubisys.de/downloads/ubisys-c4-technical-reference.pdf

Therefore configuration commands fail and a mode:null is created upon joining a new device:

"config": { "group": "20018,20019,20020,20021", "mode": null, "on": true, "reachable": true },

The recent changes for S1/S2 need to be slightly adapted to allow also configuration of the C4 device.
Older C4 devices were configured correctly in the past:

"config": { "group": "29,null,null,null", "mode": "momentary", "on": true, "reachable": true },

Steps to reproduce the behavior

Issue the following command to change the button mode:
curl -X PUT -i http://localhost:8080/api/(api-key)/sensors/(sensor-id)/config --data '{ "mode": "momentary" }'

Response:
[{"error":{"address":"/sensors/(sensor-id)/config/mode","description":"Could not set attribute","type":608}}]

Expected behavior

I would expect the message [{"success":{"/sensors/(sensor-id)/config/mode":"momentary"}}]

Screenshots

Environment

• Host system: Raspberry Pi 3
• Running method: (Raspbian / OpenHAB)
• Firmware version: 26780700
• deCONZ version 2.28.1
• Device: ConBee I
• Do you use an USB extension cable: yes
• Is there any other USB or serial devices connected to the host system? No

deCONZ Logs

No response

Additional context

No response