Migrate to bullmq

[codetheweb]

PR Checklist

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Other... Please describe:

Moves to bullmq. Partially resolves #202.

Does this PR introduce a breaking change?

[x] Yes
[ ] No

THe function signatures for job processors have changed slightly. There is no longer a DoneCallback and processors must return a Promise.

Other information

These docs need to be updated: https://docs.nestjs.com/techniques/queues

[sorensenNiels]

What can we do to get this pr into master and finalize a release

[kevinvdburgt]

What can we do to get this pr into master and finalize a release

It seems that the docs should be updated first.

@kamilmysliwiec any plans to release this migration from bull to bullmq? Or should this become another package as it contains breaking changes?

[sorensenNiels]

Releasing a bullmq package and later on deprecating the bull package would be great for most. IMHOP.

[tientp-floware]

Please merge soon, It's very helpful.

[kamilmysliwiec]

As I've mentioned in the past issues, we don't plan to migrate this package to bullmq. Instead, we'll very likely publish a separate module for this (to avoid breaking changes). Locking this PR for the time being to avoid spam (and saving it for future reference).

[kamilmysliwiec]

#1129