Entity field access condition 2281113b

Updated version of my previous patch;  I've changed branches due to some very bad problems with "git rebase".

I'm aware I have two commits that appear here.  That's the problem -- I can't get git to go lower without pulling in commits I don't own.  If you folks can tell me how to fix this, much thanks.

The patch creates the plugin and test for the issue.
fubhy --

It turns out that EntityAccessControllerInterface is not currently exposed via a service, so the $container won't know about it.  Currently, there _is_ a service for entity.manager, and I'll code to include it.

The access control can't really be injected directly right now, since each entity type has its own controller.