Implement initial InfluxDB rollup support

Currently disabled, enable with
  redis-cli set ntopng.prefs.beta_rollup 1

scripts/lua/modules/timeseries/ts_utils.lua

@@ -5,10 +5,6 @@
 local ts_utils = require("ts_utils_core")
 
 -- Include the schemas
-require("ts_second")
-require("ts_minute")
-require("ts_5min")
-require("ts_hour")
-require("ts_custom")
+ts_utils.loadSchemas()
 
 return ts_utils