Applicants vs. Time Graph Improvements

[efeichen]

Extension of #166. We would like the applicants over time graph to look nicer and have more handy features:

1. Control graph domain: allow users to see progression "in the last x days" or between "this to that date"
2. Show more data regarding applicants over time such as latest applicant count
3. Style data in ways that enhance UX (e.g. highlight or increase size of important metrics)
4. Fix misalignment between this graph and other graphs, if any
5. Fallback more elegantly on edge cases