Fixed various CMS_MODULE.install, by not marked module installed if an error occurred!

Improved Auth related module implementation by having a way to change settings like token, max age.
  - use CMS_SETUP.site_id and related "auth.$module.token" ... configuration values.
  - removed related CMS_..._CONSTANTS classes.

For auth session module, use auth_session as table name, and use VARCHAR(64).
Extracted sql from blog module, and store it under site/scripts/install.sql .
Renamed a few $modulename.sql as install.sql

examples/demo/site/modules/feed_aggregator/config/feeds.json.example

@@ -0,0 +1,28 @@
+{
+	"ids": ["news", "forum"],
+	"feeds": { 
+		"news": {
+			"title": "Eiffel related posts", 
+			"expiration": "21600",
+			"size": 5,
+			"locations": [
+					"https://bertrandmeyer.com/feed/",
+					"https://room.eiffel.com/blog/feed",
+					"https://room.eiffel.com/article/feed",
+					"https://room.eiffel.com/library/feed"
+					]
+			, "categories": ["Eiffel"]
+			,"option_description": "enabled"
+			},
+		"forum": {
+			"title": "Eiffel Forum",
+			"expiration": "21600",
+			"size": 5,
+			"locations": [
+					"https://groups.google.com/forum/feed/eiffel-users/msgs/atom.xml?num=15",
+					"http://stackoverflow.com/feeds/tag?tagnames=eiffel&sort=newest"
+				]
+			,"option_description": "enabled"
+		}
+	}
+}