Update User list functionality and design in Users.tsx

[ameliav]

🗣 Description

Update the Manage Users's page to display all Users in a paginated table view similar to the new Organizations table. Additional functionality may be applied to enhance the user experience.

💭 Motivation and context

Improves user experience and adds functionality.

🧪 Testing

Display is different and functionality works as intended.

📷 Screenshots (if appropriate)

Current unpaginated users table and rest of the page

Updated paginated users table and rest of the page

Updated pop up to invite a new user and form validation

Updated confirmation before deleting a user

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.

[Matthew-Grayson]

Looks and works great!

[nickviola]

LGTM