Create grants for resources a user owns

[BruceMacD]

When a user creates a resource they should be automatically given a grant to that resource.

Ex:

User with ID 1234 should have the following grant:
{
    identity: u:1234,
    privilege: read,
    resource: infra.users.u:1234
}

Currently we just check if the user is calling requesting their own resource.

var db *gorm.DB
if user != nil && user.ID == userID {
	db = getDB(c)
} else {
	var err error
	db, err = requireAuthorization(c, "read", "infra.groups")
	if err != nil {
		return nil, err
	}
}

This pattern can be removed when users get grants on their own resources.

[BruceMacD]

Closing for now, will re-visit