enhance quota support.

now includes:
- perOrg (users, dashboards, datasources, api_keys)
- perUser (orgs)
- global (users, orgs, dashboards, datasources, api_keys, sessions)

conf/defaults.ini

@@ -87,6 +87,7 @@ cookie_secure = false
 
 # Session life time, default is 86400
 session_life_time = 86400
+gc_interval_time = 86400
 
 #################################### Analytics ####################################
 [analytics]
@@ -253,9 +254,37 @@ exchange = grafana_events
 enabled = false
 path = /var/lib/grafana/dashboards
 
+#################################### Usage Quotas ##########################
 [quota]
 enabled = false
-user = 10
-dashboard = 100
-data_source = 10
 
+#### set quotas to -1 to make unlimited. ####
+# limit number of users per Org.
+org_user = 10
+
+# limit number of dashboards per Org.
+org_dashboard = 100
+
+# limit number of data_sources per Org.
+org_data_source = 10
+
+# limit number of api_keys per Org.
+org_api_key = 10
+
+# limit number of orgs a user can create.
+user_org = 10
+
+# Global limit of users.
+global_user = -1
+
+# global limit of orgs.
+global_org = -1
+
+# global limit of dashboards
+global_dashboard = -1
+
+# global limit of api_keys
+global_api_key = -1
+
+# global limit on number of logged in users.
+global_session = -1