mediawiki-core-jsduck-publish: Copy resources directory

The inline examples in MediaWiki core documemtation
(mediawiki.core.git:/maintenance/jsduck/eg-iframe.html) will
start referring to js files as of Ifa38338b797413b6.

Since we publish only the docs/js directly, relative paths to
"../resources" won't work. So, just like we did previously
for VisualEditor-docs, we'll copy the resources directory
over and include it in the documentation package.

Change-Id: Iec3d48866c297797d0421bcdbb7ba195e6029c8e