Feature request: have the default NimbleCharacteristicsCallbacks print the uuid of the characteristics

[jackjansen]

Not specifying your own NimbleCharacteristicsCallbacks for a characteristic you have added to your server is most likely an error.

And with the change in the API it is an error I made (because my methods that were intended didn't have the new extra argument, and I had stupidly not added the override specifier to my declaration, so my methods were quietly sitting there without being used, and the default implementations were used).

It took me a very long time until I found this bug, but if the default callbacks had printed something helpful it would have saved a lot of time.

(Note that I think this feature request holds only for NimbleCharacteristicsCallbacks set and get, because these are the only callbacks where it is probably a programmer error if you don't override them.