T332912: Users table cleanup

Summary:

• Removed users.name and users.email_verified_at
• Keep the rest of user props as UserSetting
• Add Organization field to user Profile page
• Signup asks for first and last name separately instead of a name only.

Fix tests with Laravel 6.18.8, use PHPUnit 8

Test Plan: ./phpunit

Reviewers: #hkccp_developers, vanmeeuwen

Reviewed By: #hkccp_developers, vanmeeuwen

Differential Revision: https://git.kolab.org/D1213