CB-5720 add resource-file to plugin.xml 

https://issues.apache.org/jira/browse/CB-5720

Add support for <resource-file src="glass.xml" target="xml/glass.xml" /> to a plugin's plugin.xml

The above example would copy the file glass.xml from the plugin's directory to the platforms/android/res/xml/glass.xml

This is for the use case when a plugin in needs additional file e.g. in res/xml or other directories.
An example for Android would be an authenticator that is specified in AndroidManifest.xml