uni-t-ut8803e: Initial driver skeleton.

[KonradTagowski]

It is more complex than uni-t-ut8802e. It is possible to imitate pressing the button using serial console etc., select, range, min/max by the specific command sent to the device. I am not sure how to implement this functionality in Sigrok

 case SR_CONF_SWAP:
    /* SWAP Function in this case */
        return ut8803e_send_cmd(sdi, CMD_CODE_SELECT);
    default:

I can't find another solution to add the functionality of the SELECT button, so I use the SWAP config key to do this. I suppose that the SELECT button will be helpful in measurement.

I reconstructed the protocol manually.

[biot]

Hi,

Before I review this driver, could you please check whether it's using an already-supported DMM chip, as I mentioned in PR #220? This is usually the case for UNI-T multimeters, and supporting it may be as simple as commit f5c697b.