Replace docker-sync with mutagen

[derschatta]

Is your feature request related to a problem? Please describe.
On Mac OS we use docker-sync to sync files from host to the container volumes. This is needed as a normal mounted volume performance is really slow on Mac. Using a normal named volume gives us almost native speed. But docker-sync (or rather Docker and unison) have problems syncing when a larger number of files need to by synced. The syncing just stops and you need to restart docker-sync to get it back working. There's no solution in sight. See: EugenMayer/docker-sync#646

Describe the solution you'd like
I came across a new tool called mutagen (https://mutagen.io/). It's a two-way cross-platform syncing tool. Very lightweight, easy to use. One thing mutagen promises is support for windows. This could make this project really usable on Windows as well.

Mutagen is still in a beta state but it works quite well already. I would like to replace docker-sync or at least add mutagen as a second option to the setup. Mutagen needs little setup. Should not be hard to integrate.

Describe alternatives you've considered
I've looked at some syncing tools which sync via network (Like Resilio Sync or syncthing) but the lag and performance of the sync was not that great.