add await function in crrri for vignettes with promises

[cderv]

Integrate inside the 📦 the functions await() and knit_print.promise() mentioned in #24 so that we can create some vignettes

[RLesur]

While playing with await() in vignette, I discovered that the use of later::later() in the disconnection process was suboptimal. I will try to improve those functions.