feat: allow auditors to read template insights (#10860)

- Adds a template_insights pseudo-resource
- Grants auditor and template admin roles read access on template_insights
- Updates existing RBAC checks to check for read template_insights, falling back to template update permissions where necessary
- Updates TemplateLayout to show Insights tab if can read template_insights or can update template

coderd/rbac/object_gen.go

@@ -20,6 +20,7 @@ func AllResources() []Object {
 		ResourceSystem,
 		ResourceTailnetCoordinator,
 		ResourceTemplate,
+		ResourceTemplateInsights,
 		ResourceUser,
 		ResourceUserData,
 		ResourceWildcard,