Extract generation of web ui catalog and hints from Designer build

Currently, Designer needs to fetch all the released versions of web ui to be able to generate a catalog of elements available, generate hints for codemirror, etc.
This takes too much time (and might be a source of build failures due to github timeouts/ssl handshake issues) since we need to checkout the web ui and bower install. Also, we don't need to generate everything each time we build Studio - this process is only required when a new version of the web ui is released, or some commits are done to web ui maintenance branches.

The goal of this task is to extract this process to a different QA job, possibly a downstream of the web ui jobs, and it should be responsible of publishing everything zipped to our maven repo.