add support for custom alerters

salt/elastalert/defaults.yaml

@@ -1,5 +1,6 @@
 elastalert:
   enabled: False
+  alerter_parameters: ""
   config:
     rules_folder: /opt/elastalert/rules/
     scan_subdirectories: true

salt/elastalert/map.jinja

@@ -13,3 +13,8 @@
 {% do ELASTALERTDEFAULTS.elastalert.config.update({'es_password': pillar.elasticsearch.auth.users.so_elastic_user.pass}) %}
 
 {% set ELASTALERTMERGED = salt['pillar.get']('elastalert', ELASTALERTDEFAULTS.elastalert, merge=True) %}
+
+{% set params = ELASTALERTMERGED.alerter_parameters | load_yaml %}
+{% if params != None %}
+  {% do ELASTALERTMERGED.config.update(params) %}
+{% endif %}

salt/elastalert/soc_elastalert.yaml

@@ -2,6 +2,14 @@ elastalert:
   enabled:
     description: You can enable or disable Elastalert.
     helpLink: elastalert.html
+  alerter_parameters:
+    title: Alerter Parameters
+    description: Custom configuration parameters for additional, optional alerters that can be enabled for all Sigma rules. Filter for 'Additional Alerters' in this Configuration screen to find the setting that allows these alerters to be enabled within the SOC ElastAlert module. Use YAML format for these parameters, and reference the ElastAlert 2 documentation, located at https://elastalert2.readthedocs.io, for available alerters and their required configuration parameters.
+    global: True
+    multiline: True
+    syntax: yaml
+    helpLink: elastalert.html
+    forcedType: string
   config:
     disable_rules_on_error:
       description: Disable rules on failure.