Moved bootstrap socket logic out of server

- this logic is a dependency rather than part of the server code
- moved it out ready to be moved elsewhere, doesn't need to be here

ghost/bootstrap-socket/lib/connect-and-send.js

@@ -0,0 +1,85 @@
+module.exports = (socketAddress, logging, message) => {
+    // Very basic guard against bad calls
+    if (!socketAddress || !socketAddress.host || !socketAddress.port || !logging || !logging.info || !logging.warn || !message) {
+        return Promise.resolve();
+    }
+
+    const net = require('net');
+    const client = new net.Socket();
+
+    return new Promise((resolve) => {
+        const connect = (options = {}) => {
+            let wasResolved = false;
+
+            const waitTimeout = setTimeout(() => {
+                logging.info('Bootstrap socket timed out.');
+
+                if (!client.destroyed) {
+                    client.destroy();
+                }
+
+                if (wasResolved) {
+                    return;
+                }
+
+                wasResolved = true;
+                resolve();
+            }, 1000 * 5);
+
+            client.connect(socketAddress.port, socketAddress.host, () => {
+                if (waitTimeout) {
+                    clearTimeout(waitTimeout);
+                }
+
+                client.write(JSON.stringify(message));
+
+                if (wasResolved) {
+                    return;
+                }
+
+                wasResolved = true;
+                resolve();
+            });
+
+            client.on('close', () => {
+                logging.info('Bootstrap client was closed.');
+
+                if (waitTimeout) {
+                    clearTimeout(waitTimeout);
+                }
+            });
+
+            client.on('error', (err) => {
+                logging.warn(`Can't connect to the bootstrap socket (${socketAddress.host} ${socketAddress.port}) ${err.code}.`);
+
+                client.removeAllListeners();
+
+                if (waitTimeout) {
+                    clearTimeout(waitTimeout);
+                }
+
+                if (options.tries < 3) {
+                    logging.warn(`Tries: ${options.tries}`);
+
+                    // retry
+                    logging.warn('Retrying...');
+
+                    options.tries = options.tries + 1;
+                    const retryTimeout = setTimeout(() => {
+                        clearTimeout(retryTimeout);
+                        connect(options);
+                    }, 150);
+                } else {
+                    if (wasResolved) {
+                        return;
+                    }
+
+                    wasResolved = true;
+                    resolve();
+                }
+            });
+        };
+
+        connect({tries: 0});
+    });
+};