Sometimes the nomad docker_logger may be killed by a service manager
when restarting the client for upgrades or reliability reasons.

Currently if this happens, we leak the users container and try to
reschedule over it.

This commit adds a new step to the recovery process that will spawn a
new docker logger process that will fetch logs from _the current
timestamp_. This is to avoid restarting users tasks because our logging
sidecar has failed.