TCP Zero Window alert from issue #3417 (#4684)

* Added no_if_activity alert to user script keys

* Added no_if_activity description alert

* Fixes #4648 trigger an alert when no flows are collected

* Changed the time past one call of the alert and an other

* Fixes #4648 reorganized files and cache management

* Added status flow check regarding issue #3417

* Removed debug code

Co-authored-by: matteo <biscosi@ntop.org>
Co-authored-by: Luca Deri <lucaderi@users.noreply.github.com>

scripts/plugins/alerts/network/zero_tcp_window/locales/en.lua

@@ -0,0 +1,16 @@
+--
+-- (C) 2020 - ntop.org
+--
+
+return {
+   zero_tcp_window_description = "Trigger an alert when a flow TCP window is zero",
+   zero_tcp_window_title = "Zero TCP Window",
+
+-- ####################### Status strings
+
+   status_zero_tcp_window_description = "Reported TCP window zero value for the flow: ",
+
+-- ####################### Alert strings
+
+   status_zero_tcp_window_title = "Reported TCP window zero value"
+}

scripts/plugins/alerts/network/zero_tcp_window/locales/it.lua

@@ -0,0 +1,16 @@
+--
+-- (C) 2020 - ntop.org
+--
+
+return {
+   zero_tcp_window_description = "Attiva un allarme quando la finestra di un flusso TCP è zero",
+   zero_tcp_window_title = "Zero TCP Window",
+
+-- ####################### Status strings
+
+   status_zero_tcp_window_description = "Individuato valore della finestra TCP a zero per il flusso: ",
+
+-- ####################### Alert strings
+
+   alert_zero_tcp_window_title = "Individuato valore della finestra TCP a zero"
+ }