Adds this option based on the findings of
https://github.com/python-zk/kazoo/issues/630, whereby restores of >1MB
in size would fail. This is considered an unsafe option, but given our
usecase no actual znode should ever exceed this limit; this is purely
for the large transactions that come from a `pvc task restore` action to
an empty Zookeeper instance.
We're 100% systemd here, and the lack of control/information that the
old-school ZK initscript provides is frustrating. Replace it with our
own simple unit file.
Joshua Boniface