feat: Add user roles, but do not yet enforce them (#1200)

* chore: Rework roles to be expandable by name alone

coderd/audit/table.go

@@ -42,6 +42,7 @@ var AuditableResources = auditMap(map[any]map[string]Action{
 		"created_at":      ActionIgnore, // Never changes.
 		"updated_at":      ActionIgnore, // Changes, but is implicit and not helpful in a diff.
 		"status":          ActionTrack,  // A user can update another user status
+		"rbac_roles":      ActionTrack,  // A user's roles are mutable
 	},
 	&database.Workspace{}: {
 		"id":                 ActionIgnore, // Never changes.