GH-133600: Refactor wasi.py into wasi/__main__.py

Along the way, also move related files into their appropriate directories and update `.github/CODEOWNERS`.

Author: brettcannon

.github/CODEOWNERS

@@ -298,7 +298,12 @@ Lib/test/test_interpreters/   @ericsnowcurrently
 **/*-ios*                     @freakboy3742
 
 # WebAssembly
-/Tools/wasm/                  @brettcannon @freakboy3742
+Tools/wasm/config.site-wasm32-emscripten  @freakboy3742
+/Tools/wasm/README.md         @brettcannon @freakboy3742
+/Tools/wasm/wasi-env          @brettcannon
+/Tools/wasm/wasi.py           @brettcannon
+/Tools/wasm/emscripten        @freakboy3742
+/Tools/wasm/wasi              @brettcannon
 
 # SBOM
 /Misc/externals.spdx.json     @sethmlarson

Tools/wasm/.editorconfig Tools/wasm/emscripten/.editorconfigTools/wasm/.editorconfig renamed to Tools/wasm/emscripten/.editorconfig

@@ -1,7 +1,8 @@
 #!/bin/sh
 set -e
 
-# NOTE: to be removed once no longer used in https://github.com/python/buildmaster-config/blob/main/master/custom/factories.py .
+# NOTE: to be removed once no longer used in https://github.com/python/buildmaster-config/blob/main/master/custom/factories.py ;
+#       expected in Python 3.18 as 3.13 is when `wasi.py` was introduced.
 
 # function
 usage() {