py-py-spy: add 0.4.0, and make rust & CargoPackage respect -j (#47883)

* py-py-spy: add 0.4.0

* py-py-spy: port from Package to CargoPackage

* CargoPackage: respect make_jobs

* rust: respect make_jobs during build and install

* spack style

* CargoBuilder: fix make_jobs syntax

* CargoBuilder: don't write to $HOME, use stage dir

lib/spack/spack/build_systems/cargo.py

@@ -71,13 +71,16 @@ def build_directory(self):
     @property
     def build_args(self):
         """Arguments for ``cargo build``."""
-        return []
+        return ["-j", str(self.pkg.module.make_jobs)]
 
     @property
     def check_args(self):
         """Argument for ``cargo test`` during check phase"""
         return []
 
+    def setup_build_environment(self, env):
+        env.set("CARGO_HOME", self.stage.path)
+
     def build(self, pkg, spec, prefix):
         """Runs ``cargo install`` in the source directory"""
         with fs.working_dir(self.build_directory):