Added brief readmes for all plugins. (#2184)

src/plugins/staticRootPlugin/README.md

@@ -0,0 +1,19 @@
+# Static Root Plugin
+
+This plugin takes an object tree as JSON and exposes it as a non-editable root level tree. This can be useful if you 
+have static non-editable content that you wish to expose, such as a standard set of displays that should not be edited 
+(but which can be copied and then modified if desired).
+
+Any object tree in Open MCT can be exported as JSON after installing the 
+[Import/Export plugin](../../../platform/import-export/README.md).
+
+## Installation
+``` js
+openmct.install(openmct.plugins.StaticRootPlugin('mission', 'data/static-objects.json'));
+```
+
+## Parameters
+The StaticRootPlugin takes two parameters:
+1. __namespace__: This should be a name that uniquely identifies this collection of objects.
+2. __path__: The file that the static tree should be exposed from. This will need to be a path that is reachable by a web 
+browser, ie not a path on the local file system.