feat(scripts): Add script for building all supported targets in one go

Useful when using the distributed Nix build feature.

scripts/ci-all.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+nix="$(if tty -s; then echo nom; else echo nix; fi)"
+
+set -x
+nix flake check
+$nix build -L --json --no-link --keep-going \
+  .#devShells.{x86_64-linux,{x86_64,aarch64}-darwin}.default