Update metadata records based on ActivityPub server push

[pombredanne]

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 and/or PurlDB 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 and/or PurlDB instance, including minimally reconciling conflicts.
This could include:

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