Volume mounts

[aluzzardi]

Currently, the agent expects a mount of type volume to be readily available on the machine.

Instead, we should let the agent somehow attach to said volume.

One possibility is to send the volume specification down with the task and let the agent create the volume everytime it starts an agent referencing it.

/cc @amitshukla @cpuguy83

[cpuguy83]

What does it mean to "attach" to a volume?

BTW, I have proposed a docker API addition which allows creating a volume from the container create endpoint (among other things): moby/moby#22373

[aluzzardi]

@cpuguy83 Create said volume on the machine

[amitshukla]

Implemented in: #553