Unify "Async utilities" page

[afontcu]

Same thing as #485.

Async utilities are mostly "universal", so they could live above DTL docs.

[MatanBobi]

Hi @afontcu,
I'm up for this one instead of the Firing events issue if it's still free :)

[afontcu]

Sure! 🙌

[MatanBobi]

@afontcu, I started working on this one and I just want to ask the question I asked before in #490 (comment) and is also relevant for #485.
Do we want a "Global" section after the "Getting Started" section or should we put it as part of the "Getting Started" section?

[afontcu]

Also, do you think we should build a "General"/"Universal" section? Or do you think it's related to "Getting Started"?

Hm, not sure yet. I was thinking about a sensible sidebar for docs, but didn't come up with a proposal. I'd say creating a "Global" section might do for now. It might change eventually, though!

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btw, Just to make sure efforts are in sync: this PR #499 addresses some issues with the Disappearing part of the docs, which is quite relevant to Async utilities!

[MatanBobi]

I'm removing myself from this one since there are multiple stuff going on with the events and I want to focus my mind on a different issue :)

[MatanBobi]

@alexkrolick I think we can close this one after #735 was merged, wdyt?