Add offset support on Melissa integration

Hi,

I recently got an MClimate Melissa unit from a friend to use with my A/C. I’ve quickly noticed that the temperature reported by its sensor is off by as much as 4ºC from other sensors I have.

On the app, there’s an option to set an offset for both humidity and temperature, but this does not reflect on the Home Assistant integration.

I spoke to the API developers to see if there was any way to get that information, and the response I got was that by using the https://developer-api.seemelissa.com/v1/controllers endpoint with the header Accept-Response: Advanced, this information was available.

I have since been able to confirm that this is the case, and as such, would like this to be added to the integration.

I have the same issue, both my Melissas are also about 4ºC off, I would really use the option to set an offset. They are also few % off with humidity.