r/apache-base: Factor out handlers for reuse

Roles that need to reload or restart Apache after writing configuration
files do not necessarily need to depend on the _apache_ role, but may
assume Apache is deployed in some other way.  To support this, I have
factored out the handlers from the _apache_ role into an _apache-base_
role, which such roles can list as a dependency.

roles/apache-base/handlers/main.yml

@@ -0,0 +1,9 @@
+- name: restart httpd
+  service:
+    name: httpd
+    state: restarted
+
+- name: reload httpd
+  service:
+    name: httpd
+    state: reloaded