refactor(pkg): switch to Stdune maps (#11314) #29581

Job	Run time
Nix (macos-latest)	2m 13s
Build (macos-latest, 5.1.x)	15m 58s
Nix (ubuntu-latest)	53s
Documentation	57s
Build (ubuntu-latest, 5.1.x)	8m 28s
Build (ocaml-variants.5.4.0+trunk, ubuntu-latest, true)	1m 29s
Build (4.14.x, ubuntu-latest, true)	1m 26s
Format	1m 8s
Coq 8.16.1	7m 9s
Build (4.14.x, macos-latest, true)	2m 28s
Wasm_of_ocaml	10m 32s
Build (5.1.x, macos-13, true)	5m 29s
Build (ocaml-base-compiler.4.14.2,system-msvc, windows-latest)	14m 14s
Build (ocaml-base-compiler.5.1.1,system-mingw, windows-latest)	8m 21s
Build microbenchmarks	2m 30s
Build (4.08.x, ubuntu-latest, true)	1m 31s
Build (4.04.x, ubuntu-latest, true, true)	4m 21s
Build (4.02.x, ubuntu-latest, true)	3m 50s
Create local opam switch (macos-latest, 5)	7m 30s
Create local opam switch (macos-latest, 4.14)	7m 57s
Create local opam switch (ubuntu-latest, 5)	4m 54s
Build monorepo benchmark docker image	4m 4s
Create local opam switch (ubuntu-latest, 4.14)	4m 55s
	2h 2m 17s

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