Update VulnerableCode on AP server PUSH

[pombredanne]

This is a follow up from #15 here for VulnerableCode only:

In a decentralized scenario, there are two or more servers cooperating. Here I would like to start building this multiserver architecture. Specifically, we should build an application to run in a second VulnerableCode server that can receive updates notifications from the FederatedCode ActivityPub server for a package and then fetch the data from the backing git stores. And use this to update this separate VulnerableCode instance, including minimally reconciling conflicts.

• Create script(s) to fetch the backing data from the corresponding FederatedCode backing Git repository and update the local records in VulnerableCode reconciling conflicts as needed #55
• Create the function(s)/services to receive updates notifications from the FederatedCode ActivityPub server in VulnerableCode #56