feat: add immediately option for every repeatable job

[HugoPoi]

Try to resolve #1239

• immediately not implemented with cron
• my changes in the createNextJob function are not pretty, maybe add a delete opts.immediately should be better because with the present code it will always be saved in redis ?
• My unit test doesn't cover lot of cases

[coveralls]

Coverage increased (+0.7%) to 93.777% when pulling ae0e227 on HugoPoi:develop into 01f8154 on OptimalBits:develop.

[Eywek]

Any news on this?

[HugoPoi]

I need someone to review it. And it might be useful to have #1498 with this.

[oskarstrasburger]

Any news @manast ?

[faller]

Any news?

[manast]

I would merge this but my last comment needs to be addressed!

[HugoPoi]

Ok so I need to refactor, passing the flag directly in opts.immediately because it will need to be handle only at the first iteration and not saved in Redis. And no mutation, so no delete, no assignment with =.

[joaozitopolo]

Same problem here. I need to skip the first execution.
If the object "job" on process had a execution count, or a firstRun flag, we can do the skip in the process function.

[santiq]

@HugoPoi hey man I know it's been a year but could you do those changes? I'll be happy to help.

[HugoPoi]

I have rebase the change on develop, an immediately flag will be saved in redis is it bad ? I think not.
If we don't want to save the immediately flag in db, need a change to the deepDefault to omit the prop.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[manast]

If somebody wants to fix this PR it is just a matter of backporting this PR from BullMQ: taskforcesh/bullmq#536