I can't take credit for much of the work here -- I adapted it from this blog post: https://tech.willhaben.at/mongodb-incremental-backups-dff4c8f54d58
My main contribution was to make it a little easier to use with docker as well as numerous little cleanup tasks. I also made it gzip the oplog backups and added support for SSL connections
Note that I havne't yet tested the point in time restore script; it likely needs work, particularly to make things work with the gzipped oplog files