account data export

[grarer]

for compliance with internet regulations, we need to make it possible to download a human-readable and machine-readable exported version of their user data. For us this means their account info, friends, status, and profile (although profiles are not yet implemented). This should probably be a human-readable json file like

{
    "username": "alice",
    "fullName": "Alice Exampleton",
    "friendlyName": "Alice",
    "gender": "Female",
    "email": "alice@example.com",
    "birthDate": "1995-03-05",
    "friends": [
        {
            "username": "bob",
            "fullName": "Robert Defacto",
            "friendlyName": "Bob"
        },
        {
            "username": "charlie",
            "fullName": "Charlie McExampleface",
            "friendlyName": "Charlie"
        }
    ],
    "statusMessage": null,
    "doNotDisturb": false
}

This should not include user UUIDs, since those are an internal representation specific to boop. Users' friends should be identified by their names and usernames, not their UUIDs.

The json-beautify package looks like a good choice for rendering the object into JSON that has whitespace for human-readability, rather than JSON.stringify() which puts everything on one line and is not very human readable.