Allow to disable parallel taks limit

[ClementNerma]

A detailed description of the feature you would like to see added.

Allow to disable the limits of parallel running tasks. Idea of implementation: pueue parallel 0 would disable any limit (like many othe rtools do).

Explain your usecase of the requested feature

Not needing to worry about the parallel tasks limit undependently of the usage of pueue.

Alternatives

No response

Additional context

No response

[Nukesor]

I actually like that proposal quite a lot. It's also a reasonable alternative solution to #499.

I assume this shouldn't be too hard to implement, I'll take a look in the next few days :)

[Nukesor]

Implemented the behavior in the linked MR.
Also tested it properly on my local setup and it works as expected :)

[ClementNerma]

Ha, I was about to submit my own PR for this but you beat me to it xD
Thanks for the feature!