Switch from async-lock to tokio primitives

[nazar-pc]

I discovered that smol-rs/async-lock#91 not only affects RwLock, but also Mutex and possibly other primitives (we used Semaphore too in some case). So I decided to move away from it completely (though I did like API of async-lock more).

We still use async-lock in our fork of Substrate for parallel block verification implementation, I'll take care of it when we update Substrate again (should be soon, they're polishing September's release at the moment).

Code contributor checklist:

• I have read, understood and followed contributing guide

[nazar-pc]

Apparently this doesn't fix the issue fully either 🤔

[teor2345]

Looks fairly straightforward, do you think it’s Substrate causing the remaining issues?

[nazar-pc]

No, the issue is on the farmer, we have zero Substrate dependencies used there.

It is possible that the issue is actually in event-listener, which async-lock is based on and what we use directly in farmer too. See linked issue and links that follow from there.

[nazar-pc]

Fix for underlying issue was merged in #3041, this doesn't fix anything