Create a reusable IG Switch component with UIDocs and snapshot test

Summary: Switch is a standard component and needs some extra styling of the colors to be used in IG, so I've created a reusable switch component for Instagram React Native and added server snapshot tests with UIDocs for it so it will appear in https://our.intern.facebook.com/intern/uidocs/?docset=rn_iig for more people to use.

Reviewed By: lostatseajoshua

Differential Revision: D9023261

fbshipit-source-id: dd460ca4506e2fc072ed03cca56b4a3c172123bd

Author: Trish Saylor

Libraries/Components/Switch/Switch.js

@@ -21,7 +21,7 @@ const requireNativeComponent = require('requireNativeComponent');
 import type {ColorValue} from 'StyleSheetTypes';
 import type {ViewProps} from 'ViewPropTypes';
 
-type Props = $ReadOnly<{|
+export type Props = $ReadOnly<{|
   ...ViewProps,
   /**
    * The value of the switch.  If true the switch will be turned on.