Support engine configuration

pillar.example

       # filter to use for Most other LDAP servers
     auth.ldap.filter: {% raw %}'uid={{ username }}'{% endraw %}
 
+    # optional engine configuration
+    engines:
+      slack:
+        token: xoxp-XXXXX-XXXXXXX
+        control: True
+        valid_users:
+          - someuser
+          - otheruser
+        valid_commands:
+          - test.ping
+          - list_jobs
+        aliases:
+          list_jobs:
+            type: runner
+            cmd: jobs.list_jobs
+
   # salt minion config:
   minion:
 

salt/files/master.d/engine.conf

+#
+# This file is managed by Salt! Do not edit by hand!
+#
+{%- set engines = salt['pillar.get']('salt:engines') -%}
+{%- if engines %}
+engines:
+  {{ engines | yaml(False) | indent(2) }}
+{%- endif -%}