Make BullMQ Deno compatible

[manast]

Is your feature request related to a problem? Please describe.
We do not officially support Deno. As there is a growing community, it makes sense to also support it.

Describe the solution you'd like
Make the minimal changes necessary to achieve compatibility so that the whole test suite can be run via Deno, that would gives us some guarantees that the library is indeed working properly in this environment. The tests should run automatically in GitHub actions as we do with the rest.

Describe alternatives you've considered
None

Additional context
It is possible that some code changes are necessary, but I am not sure: https://docs.deno.com/runtime/fundamentals/node/

Some changes in the test runner may be necessary as Deno requires the npm specifier to be used when importing node modules:

import  { Queue, Worker } from "npm:bullmq"

The question is how to run the tests without doing this change in all the tests (which btw is not compatible with Node so that would require duplicating them, or creating some generic "import" module that works with both runtimes. In any case, we do not want to create code duplication to achieve our goals here.