conf: add config files to module directories

The idea here is that the config files in the module directories will
serve as the canonical documentation of all module configuration
options.

src/mod/applications/mod_http_cache/conf/autoload_configs/http_cache.conf.xml

@@ -0,0 +1,8 @@
+<configuration name="http_cache.conf" description="HTTP GET cache">
+  <settings>
+    <param name="max-urls" value="10000"/>
+    <param name="location" value="$${base_dir}/http_cache"/>
+    <param name="default-max-age" value="86400"/>
+  </settings>
+</configuration>
+

src/mod/applications/mod_http_cache/conf/dialplan/http_cache.xml

@@ -0,0 +1,7 @@
+<include>
+	<extension "http_cache_demo">
+		<condition field="destination_number" expression="^(.*)$">
+			<action application="playback" data="${http_get(http://myserver.yo/media/hello_world.wav)}"/>
+		</condition>
+	</extension>
+</include>