Support building free-threaded CPython (#319)

* Support building free-threaded CPython

Add support for Python's free threading build mode where the global
interpreter lock is disabled. The packages are marked using a suffix on
the architecture, like 'x64-freethreaded' or 'arm64-freethreaded'.

* Match '-freethreaded' in arch

* Use type 'string' instead of 'str'

* On Linux, only delete Python installations with the same architecture.

This matches the macOS behavior and allows users to install both the
free-threading and default builds at the same time.

config/macos-pkg-choices-default.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<array>
+    <dict>
+   </dict>
+</array>
+</plist>

config/macos-pkg-choices-freethreaded.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<array>
+    <dict>
+        <key>attributeSetting</key>
+        <integer>1</integer>
+        <key>choiceAttribute</key>
+        <string>selected</string>
+        <key>choiceIdentifier</key>
+        <string>org.python.Python.PythonTFramework-{{__VERSION_MAJOR_MINOR__}}</string>
+    </dict>
+</array>
+</plist>

config/python-manifest-config.json

@@ -1,5 +1,5 @@
 {
-    "regex": "python-\\d+\\.\\d+\\.\\d+-(\\w+\\.\\d+)?-?(\\w+)-(\\d+\\.\\d+)?-?((x|arm)\\d+)",
+    "regex": "python-\\d+\\.\\d+\\.\\d+-(\\w+\\.\\d+)?-?(\\w+)-(\\d+\\.\\d+)?-?((x|arm)\\d+(-freethreaded)?)",
     "groups": {
         "arch": 4,
         "platform": 2,