Fix TemplateProcessorComponent to register the invalidator after the cluster service has started

ComponentManagerImpl#start works in 2 phasis : https://github.com/nuxeo/nuxeo-lts/blob/2021/modules/runtime/nuxeo-runtime/src/main/java/org/nuxeo/runtime/model/impl/ComponentManagerImpl.java#L828-L844

1. activation of components
2. start of components

The activation of components calls TemplateProcessorComponent#activate which tries to register an invalidator (if the cluster service indicates that the cluster is enabled).
The start of components (which is done after the activation) calls ClusterServiceImpl#start which will configure the cluster options based on the cluster configuration

Observed behavior: Because of this order, TemplateProcessorComponent#activate never knows if a cluster is enabled

Expected behavior: Make TemplateProcessorComponent#registerInvalidator be called once the cluster service has registered the cluster configuration