Standardize the naming and attributes of ancillary time arrays across components

A request from @phillips-ad, based on user input:

> Standardize the naming and attributes of ancillary time arrays across components. (time_bnds in cam, time_bounds in clm, no calendar attribute set for either, etc..)

@klindsay28 points out that well-written scripts shouldn't require uniformity in names across components. However, I feel like this is something that might be relatively easy to standardize and could save significantly more time than it takes us to make the change, so we might as well do it.

I'm not sure exactly what needs to be done. When someone gets a chance to coordinate this, we should open issues in the respective component repositories asking for changes and note those issues here to track them.