Merge pull request #430 from Security-Onion-Solutions/kibana_7_dark_mode

UI Dark Mode

salt/kibana/etc/config.json

@@ -3,6 +3,7 @@
     "defaultIndex": "*:so-*",
 		"discover:sampleSize":"100",
 	  "dashboard:defaultDarkTheme":true,
+	  "theme:darkMode":true,
 	  "timepicker:timeDefaults":"{\n  \"from\": \"now-24h\",\n  \"to\": \"now\",\n  \"mode\": \"quick\"\n}"
 	}
 }