Roles Update

[JasonIsAzn]

Overview

• Remove Lead power can no longer:
  • manually sign in/out user of event
  • access admin dashboard (only frontend side)
  • update roles
• Add 'Coach' role and can only create/edit event and view QRCodes
  • This is to reduce micro-mangement of intramural practice events
• Update Firebase rules to include coach to change event document

[LucientZ]

I went in and added some documentation to the hasPrivileges function. Other than that, approved. Glad this is abstracted since the boolean chains were getting pretty long and annoying.