Refactors alerts and flow statuses in builtin and plugins

Implements #3811
Implements #3812

Refactors builtin alerts

Refactors builtin flow statuses

scripts/lua/modules/alert_definitions/alert_login_failed.lua

@@ -0,0 +1,20 @@
+--
+-- (C) 2019-20 - ntop.org
+--
+
+local alert_keys = require "alert_keys"
+
+local function loginFailedFormatter(ifid, alert, info)
+  return(i18n("user_activity.login_not_authorized", {
+    user = alert.alert_entity_val,
+  }))
+end
+
+-- #######################################################
+
+return {
+  alert_key = alert_keys.ntopng.alert_login_failed,
+  i18n_title = "alerts_dashboard.login_failed",
+  i18n_description = loginFailedFormatter,
+  icon = "fas fa-sign-in",
+}