Target all e2e datacenters for system and sysbatch e2e tests. They
require that the system jobs run on all linux clients.
However, the jobs currenly only target `dc1` datacenter, but the nightly
e2e cluster has 4 clients spread in `dc1` and `dc2` datacenters, causing
the tests to fail.
I missed this problem in e2e dev cluster because it only used a single
dc1 datacenter.
This PR implements a new "System Batch" scheduler type. Jobs can
make use of this new scheduler by setting their type to 'sysbatch'.
Like the name implies, sysbatch can be thought of as a hybrid between
system and batch jobs - it is for running short lived jobs intended to
run on every compatible node in the cluster.
As with batch jobs, sysbatch jobs can also be periodic and/or parameterized
dispatch jobs. A sysbatch job is considered complete when it has been run
on all compatible nodes until reaching a terminal state (success or failed
on retries).
Feasibility and preemption are governed the same as with system jobs. In
this PR, the update stanza is not yet supported. The update stanza is sill
limited in functionality for the underlying system scheduler, and is
not useful yet for sysbatch jobs. Further work in #4740 will improve
support for the update stanza and deployments.
Closes#2527
