proper naming and actually using the state

hardware/raspberrypi/init.sls

@@ -1,4 +1,9 @@
- 
+{%
+set has_promeexporter = salt['pillar.get'](
+  'prometheus:service:wanted',
+  default=False
+%}
+
 {%
 set has_fan = salt['pillar.get'](
   'hardware:raspberrypi:fan:has_fan',
@@ -6,7 +11,10 @@ set has_fan = salt['pillar.get'](
 )
 %}
 
-{%- if has_fan %}
 include:
+{%- if 'node_exporter' in has_promexporter %}
+ - .prometheus-exporter
+{%- endif %}
+{%- if has_fan %}
   - .fan
 {%- endif %}