add support for custom alerters

salt/soc/soc_soc.yaml

@@ -83,6 +83,13 @@ soc:
         advanced: True
       modules:
         elastalertengine:
+          additionalAlerters:
+            title: Additional Alerters
+            description: Specify additional alerters to enable for all Sigma rules, one alerter name per line. Alerters refers to ElastAlert 2 alerters, as documented at https://elastalert2.readthedocs.io. Note that the configuration parameters for these alerters must be provided in the ElastAlert configuration section. Filter for 'Alerter Parameters' to find this related setting.
+            global: True
+            helpLink: sigma.html
+            forcedType: "[]string"
+            multiline: True
           allowRegex:
             description: 'Regex used to filter imported Sigma rules. Deny regex takes precedence over the Allow regex setting.'
             global: True