feat(nix): add wasi32 cross target

[dhess]

No description provided.

[dhess]

Remaining issues:

• Get to the bottom of the GHC Wasm internal error when compiling generics-sop: https://buildkite.com/hackworthltd/primer-ci/builds/434/steps/canvas?sid=019901cd-f7af-4411-8cc1-c76e9180c068#0199027c-81c4-492d-ae6d-01864b3e6850/21-46. Note that the ghc-wasm-meta version of the compiler does not hit this issue. (Tracked in wasi32 cross target GHC failure input-output-hk/haskell.nix#2435)
• Figure out what to do about tasty-discover tests. In our current non-Nix workflow, we bake them out before running the tests under Wasm using wasmtime:

  primer/primer/Makefile.wasm32

  Line 17 in 16f43c5

  tasty-discover test/Test.hs _ test/TestsWasm32.hs --tree-display

  . It's not clear how to port this to the Haskell.nix infrastructure.
• Add some Nix bits to run the frontend distribution prep in https://github.com/hackworthltd/primer/blob/main/primer-miso/build-frontend.sh. This should be relatively straightforward, once we have a working build in Nix.
• Need to port the benchmarks to tasty-bench (feat: build & run primer-benchmark for Wasm32 targets #1190). Note that at the moment, in this PR, I've removed the benchmarks temporarily to get things moving forward — Wasm benchmarks are low priority.