Add support for 1/3-term Course 5 labs

[psvenk]

We got an email about chemistry lab modules showing incorrect times, which should be fixed once venkatesh-sivaraman/fireroad-server@67433d8f09 is propagated. However, a related issue is that Hydrant does not have support for classes with arbitrary start/end times; we can instead parse the quarter information from FireRoad.

[cjquines]

oh wow, 1/3-terms??? that's new

if we want arbitrary start/end times, the big ones to change are activity.ts:Event and dates.ts

i'm not even sure we correctly export h1/h2 classes...