chore: allow a waku node to act as a store client

[richard-ramos]

Background

logos-messaging/logos-messaging-nim#2420

Pre-requisite

logos-messaging/logos-messaging-nim#2457

Details

• The node should handle properly a configuration setting (storenode) that contains a multiaddress of a store node that can be queried.
• Also implement an example that helps to test that feature