fix: template: enforce bounds of template max_ttl (#3662)

This PR makes the following changes:

- enforces lower and upper limits on template `max_ttl_ms`
- adds a migration to enforce 7-day cap on `max_ttl`
- allows setting template `max_ttl` to 0
- updates template edit CLI help to be clearer

coderd/authorize.go

@@ -49,6 +49,7 @@ func (api *API) Authorize(r *http.Request, action rbac.Action, object rbac.Objec
 // This function will log appropriately, but the caller must return an
 // error to the api client.
 // Eg:
+//
 //	if !h.Authorize(...) {
 //		httpapi.Forbidden(rw)
 //		return