Trailing stop on exchange

Describe the enhancement

Hi guys! I wondered if it was possible to implement the trailing stop directly on the exchange. I saw that it was available in most of the exchanges, even Kraken Pro added it very recently.

I think it could be a good thing as it gives trades a better reliability and Freqtrade won't make any API calls to adjust manually the stop loss.

What do you guys think about it?

Thanks!