conventional naming for differing emergency durations on a jointly owned facility

[catkins-miso]

Say TO1's facility rating methodology has the following emergency durations in minutes: 240, 60, 10
Now TO2 owns part of the facility, and the choose to submit their own ratings. Suppose TO2's methodology has 30 minute and 5-minute emergency ratings, and the RC requires a 30-minute and 5-minute rating.

The Clearinghouse should consider the TO1's 60-minute rating and TO2's 30-minute rating when determining the RC's 30-minute limit. Likewise, the TO1 10-minute and TO2 5-minute for the RC's 5-minute limit.

Now, the detailed limits snapshot must reflect the actual emergency duration of the original ratings proposals.

The spec doesn't need updated to accommodate this requirement, but I think we should suggest a convention for the names used in the default-emergency-durations header, e.g., emergency-60 and emergency-10, in addition to the RC's emergency and load-shed. The name provided by the RP in the proposal isn't necessary to preserve.