Arvados

I'm open to a discussion/bikeshedding on this, but: I knew this section existed, and the first place I went to look for it was our "a-c-r options" page, because I think of it as an a-c-r feature, not a CWL thing. Instead it's on cwl-style.html, "Guidelines for Writing High-Performance Portable Workflows." Even if you think of it as a CWL feature, it seems like a generally useful feature, not one limited to performance or style considerations.

IMO the main place this documentation should live is the "a-c-r options" page. If we want to link back to it from cwl-style.html, that's fine, we have other pointers like that throughout the page already.