Cohorts

[shiquan-lim]

Implemented cohort functionality.

Use cases as follows:

• Cohort navigation
• Creation of new cohort, selection of existing events to include
• Create new announcements for cohorts
• View cohort announcements
• Navigate to joined event from cohort
• Cohort access restriction according to events

Misc enhancements:

• Loading bar for code challenges
• Fixed placeholder spelling errors which prevented labels from appearing
• Implemented tooltips for certain icons