lib: Add zephyr queue functionality

[nordicjm]

Adds queue functionality, taken from zephyr kernel code

[lemrey]

We should definitely not have a /kernel folder here. For now, you could copy it as-is into the application folder where you need it and carry on.

Down the road, I think it would be best to make a generic queue library that has the same characteristic as this one (list based and dynamic, no-copy), and has its own bm_ API. Then we glue it to the k_queue APIs with macros. This way we could have a simpler library with no Zephyr leftovers, that would be more re-usable.

[nordicjm]

We should definitely not have a /kernel folder here. For now, you could copy it as-is into the application folder where you need it and carry on.

It's needed by multiple applications so that will not work, it needs a central location

Down the road, I think it would be best to make a generic queue library that has the same characteristic as this one (list based and dynamic, no-copy), and has its own bm_ API. Then we glue it to the k_queue APIs with macros. This way we could have a simpler library with no Zephyr leftovers, that would be more re-usable.

That's a no, this is needed for reuse of zephyr code as-is, as explained in the call. If you really want to rewrite it and verify it is functionally identical and that nothing breaks then you can do that, but I will not be doing that

[lemrey]

It's needed by multiple applications so that will not work, it needs a central location

I see, thanks for clarifying. Please have a look if #162 would work for you.

[knutel-nordic]

Add link to the revision this was copied from?

[eivindj-nordic]

Not reviewed very thoroughly as we plan to remove this when #162 is tested and ready.

[lemrey]

Made a comment thinking it was a different PR, and have deleted it 🙊

[eivindj-nordic]

@nrfconnect/ncs-code-owners @nrfconnect/ncs-co-build-system Please review.