[WIP] Revamp #1985 - Aa lower lib

[edi33416]

This is an attempt to continue @somzzz 's work. Please see #1985 for reference

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[thewilsonator]

perhaps alias AssocArray!(void, void) to AA, to avoid repetition.

[wilzbach]

As this wasn't referenced, there's also this previous effort which contains a lot of discussions.

[RazvanN7]

cc @teodutu