Add support for regulation A1a (attempt and cumulative time limits)

[coder13]

Now that the edit events page refactor has been done, we should be able to think about how to support this reg in the wcif.

Regulation A1a

[coder13]

One option would be to simply have timelimit and cumulativeTimelimit fields on the round object both with different types. A round will have at minimum one of these and at most both. Either could be null.