fix(go api): Catch panics, and check health of databases

[michaelkedar]

• Made all spawned goroutines recover from panics and return an error, so as to not crash the whole API if one request is bad.
• To accomplish this, make a safe package for the boilerplate of the defer recover statements.
• Made the health checks ping the database (Datastore and GCS) every so often so that critical unrecoverable errors do eventually get the server killed.