[Feature] User role

[alexjustesen]

Description

This PR introduces roles for users, restricts authorization based on policies and lays the ground work for some future improvements.

Closes #511

Notes

• When this feature is released the first user will be given the admin role.

Roles

See the Authorization docs for a detailed explanation of what each role and and cannot do.

• admin
• guest
• user

Changelog

Added

• cli command to update a user's role
• role to the User model
• scope page and resource authorization to the new roles

Changed

• reorganized the form and table for UserResource

Screenshots

Updated user resource