Selecting which graphs to show with config option

Known-good facts to graph are set as defaults. This list is merged
with whatever facts are listed in settings.py

puppetboard/templates/fact.html

@@ -2,7 +2,9 @@
 {% import '_macros.html' as macros %}
 {% block content %}
 <h1>{{name}}{% if value %}/{{value}}{% endif %} ({{facts|length}})</h1>
+{% if render_graph %}
 {{macros.facts_graph(facts, autofocus=True, show_node=True, margin_bottom=10)}}
+{% endif %}
 {% if value %}
 {{macros.facts_table(facts, autofocus=True, show_node=True, show_value=False, margin_bottom=10)}}
 {% else %}