Add jitter to scheduler

Description

It would be nice if the @Scheduled annotation also support setting a jitter.

We have multiple instances running which are doing periodical tasks / checks. Adding a jitter would better distribute the load of the task randomly.

Implementation ideas

It could be added to the @Scheduled annotation similar as it is done in the @Retry annotation.

[mkouba]

I must admit that I find the idea interesting. OTOH in most cases the goal of a scheduler method is to execute some logic at a specific time or at a specific interval 😉. Could you be a little more specific about the expected behavior? For example, what exactly should happen if you define @Scheduled(every = "10s", jitter = "1000")? Should it be executed somewhere between interval - 1000ms and interval + 1000ms?

CC @machi1990

[mkouba]

Note that this could be difficult (if at all possible) to implement in quarkus-quartz.