Refactor frontend to remove old files

[jtucholski]

After many new features and refactorings, we have several Components and types in the codebase that are no longer used. This task involves looking at these component files in question, verifying that they are no longer used/needed, and removing them to keep our codebase clean.

Note:

• At any point if you see this file is in use, reconsider removing it. Talk it through with someone on the team.
• Also- please do not remove UserActivity.tsx. It is not in use but it will be required in the future.

Components

• Remove Users.tsx file
  • we now have admin and student management so no need for this file (leftover from PR 382 split user management into students and admins #400)
• Remove ResponsiveNavLink.tsx
  • not sure what this is for but seems like code from old
• Remove NavLink.tsx
• Remove NotificationCard.tsx
• Remove NotificationSideBar.tsx
• Remove CategoryItem.tsx

Types: Please make sure to remove relevant interfaces/enums from the common.ts file if needed.

• Remove ToastProps
• Remove Resource
• Remove Link