Update site with dates for Cohort 1, 2024

[mentalcaries]

The dates for Cohort 1, 2024 need to be updated on the website:

• Application window opens on Jan 21, 2024
• Application window closes: Jan 28, 2024
• Cohort kickoff: Feb 4, 2024
• Regions: North America, Europe/Africa, South Asia
• iCal .ics file should also be updated