Added support for allowing alerts to un-ack (#9136)

* Add support for allowing alerts to un-ack

* Updated db_schema.yaml

* Update and rename 263.sql to 265.sql

* Fix up ui a bit.

* Renamed sql file

doc/Alerting/Introduction.md

@@ -0,0 +1,34 @@
+source: Alerting/Introduction.md
+
+# Introduction
+
+To get started, you first need some alert rules which will react to changes with your devices before raising an alert.
+
+[Creating alert rules](Rules.md)
+
+After that you also need to tell LibreNMS how to notify you when an alert is raised, this is done using `Alert Transports`.
+
+[Configuring alert transports](Transports.md)
+
+The next step is not strictly required but most people find it useful. Creating custom alert templates will help you get 
+the benefit out of the alert system in general. Whilst we include a default template, it is limited in the data that you 
+will receive in the alerts.
+
+[Configuring alert templates](Templates.md)
+
+### Managing alerts
+
+When an alert has triggered you will see these in the Alerts -> Notifications page within the Web UI.
+
+This list has a couple of options available to it and we'll explain what these are here.
+
+#### ACK
+This column provides you visibility on the status of the alert:
+![ack alert](img/ack.png) This alert is currently active and sending alerts. Click this icon to acknowledge the alert.
+![unack alert](img/unack.png) This alert is currently acknowledged until the alert clears. Click this icon to un-acknowledge the alert.
+![unack alert until fault worsens](img/nunack.png) This alert is currently acknowledged until the alert worsens or gets 
+better, at which stage it will be automatically unacknowledged and alerts will resume. Click this icon to un-acknowledge the alert.
+
+#### Notes
+This column will allow you access to the acknowledge/unacknowledge notes for this alert.
+![alert notes](img/notes.png)

doc/Alerting/index.md

@@ -9,6 +9,7 @@ The system requires a set of user-defined rules to evaluate the situation of eac
 
 Table of Content:
 
+- [Introduction](Introduction.md)
 - [Rules](Rules.md)
     - [Syntax](Rules.md#syntax)
     - [Options](Rules.md#options)