bpo-34605: Avoid master/slave terms (GH-9101)

* Replace "master process" with "parent process"
* Replace "master option mappings" with "main option mappings"
* Replace "master pattern object" with "main pattern object"
* ssl: replace "master" with "server"
* And some other similar changes

command/install.py

@@ -223,7 +223,7 @@ class install(Command):
 
     def finalize_options(self):
         """Finalizes options."""
-        # This method (and its pliant slaves, like 'finalize_unix()',
+        # This method (and its pliant childs, like 'finalize_unix()',
         # 'finalize_other()', and 'select_scheme()') is where the default
         # installation directories for modules, extension modules, and
         # anything else we care to install from a Python module