Create EventSignUp Component (Closes #27)

[hnadrian]

Developer: Adrian Nguyen, Kasey Liu, Amanda Chan, Charles Moreno, Ivan A, Kayla Tran, Xavier Garcia

Closes #27

Pull Request Summary

Creates EventSignUp component where volunteers can sign up to be volunteers for events.

Modifications

• New branch in addition to 27-EventSignUp-component to fix merging issues.
• Submission retrieves the logged-in user's email to retrieve volunteerId.
• Use ChakraReactSelect wrapper for multiple role selection.
• Rework UI code to use mostly ChakraUI and minimal CSS.
• Implement states and form fields state updates for submission.
• Various error handling for login state as well as form inputs before submission.
• Events drop-down is on future events only.

Pull Request Checklist

• [x] Code is neat, readable, and works
• [x] Comments are appropriate
• [x] The commit messages follows our guidelines
• [x] The developer name is specified
• [x] The summary is completed
• [x] Assign reviewers

Screenshots/Screencast

[hnadrian]

Some new updates added:

• Prefilled event when choosing from UserEventDetails
• Gray out button if the event has passed from UserEventDetails
• Collapsible role description under each shift
• Fix role selection not cleared when switching events