Add status icons to approved, ongoing and finished contests on the contests page

[dmint789]

The contests page should make it clear what status each contest has currently. This can be done in the form of an icon in front of the date, same as on the WCA website.

• For approved contests (contest.state === ContestState.Approved), use the hourglass-start Font Awesome icon
• For ongoing contests, use the hourglass-half icon. This status should be determined using the same logic as on line 26 in client/app/competitions/[id]/page.tsx (that logic should be moved into a new getIsContestOngoing() function in client/helpers/utilityFunctions.ts).
• For finished contests (contest.state === ContestState.Finished), use the hourglass-start icon rotated 180 degrees, because the hourglass-end icon requires the premium version of Font Awesome.