Allow some items to opt out of emergency closing handler

[Jane Sandberg]

ILLs have specific due dates that are dictated by the lending library. As such, they should not have their due dates automatically extended by the emergency closing handler, because the new due date will not be accurate according to the lending library.

We have a specific circmod and shelving location for our ILLs, but I know that other libraries have other systems for indicating their ILLs. If we could opt that circmod or shelving location out from the emergency closing handler, we wouldn't be giving those bad due dates to our patrons.