Stop using a separate module for the PgM Guide.

asamalik says there's no real value in it, and we're going to have
everything live under docs.fp.o/program_management anyway.

antora.yml

@@ -3,14 +3,14 @@
 name: fedora  # <---- PLEASE MODIFY
 
 # Title will be visible on the page. 
-title: Fedora Program Management Guide # <---- PLEASE MODIFY
+title: Fedora Program Management # <---- PLEASE MODIFY
 
 # If you don't plan to have multiple versions of the docs (for example, to document multiple versions of some software), you can ignore this field. Otherwise, change "master" to a specific version.
 version: master
 
 # We encourage you to name the index page as "index.adoc". If you absolutely have to use a different name, please reflect it here. You can ignore this field otherwise. 
-#start_page: pgm_guide:index.adoc
+start_page: ROOT:index.adoc
 
 # This lists all the menu definitions of your component.
 nav:
-- modules/pgm_guide/nav.adoc
+- modules/ROOT/nav.adoc

site.yml

@@ -1,6 +1,6 @@
 site: 
   title: Local Preview
-  start_page: fedora:pgm_guide:index.adoc
+  start_page: fedora:ROOT:index.adoc
 content:
   sources:
    - url: .