Add documentation for the packaging module.

This updates the user guide to refer to Packaging instead of Distutils.
Some files still require an update.
diff --git a/Doc/tools/sphinxext/indexcontent.html b/Doc/tools/sphinxext/indexcontent.html
index d5e17cd..10f9d26 100644
--- a/Doc/tools/sphinxext/indexcontent.html
+++ b/Doc/tools/sphinxext/indexcontent.html
@@ -20,9 +20,9 @@
          <span class="linkdescr">tutorial for C/C++ programmers</span></p>
       <p class="biglink"><a class="biglink" href="{{ pathto("c-api/index") }}">Python/C API</a><br/>
          <span class="linkdescr">reference for C/C++ programmers</span></p>
-      <p class="biglink"><a class="biglink" href="{{ pathto("install/index") }}">Installing Python Modules</a><br/>
+      <p class="biglink"><a class="biglink" href="{{ pathto("install/index") }}">Installing Python Projects</a><br/>
          <span class="linkdescr">information for installers &amp; sys-admins</span></p>
-      <p class="biglink"><a class="biglink" href="{{ pathto("distutils/index") }}">Distributing Python Modules</a><br/>
+      <p class="biglink"><a class="biglink" href="{{ pathto("packaging/index") }}">Distributing Python Projects</a><br/>
          <span class="linkdescr">sharing modules with others</span></p>
       <p class="biglink"><a class="biglink" href="{{ pathto("documenting/index") }}">Documenting Python</a><br/>
          <span class="linkdescr">guide for documentation authors</span></p>