Use Galaxy Pulsar for all jobs regardless of destination

[innovate-invent]

Example for k8s: galaxyproject/pulsar@f892f71

[innovate-invent]

It may be better to replace pulsar with two scripts added to the galaxy repository.
The scripts would provide CLI access to the logic within galaxy that stages, prepares, and cleans up galaxy jobs.
This can then be used to schedule jobs where there is no required filesystem.
Pulsar has already done much of this work and the logic largely needs to be just ripped out of it.

The k8s runner can then be rewritten to use a job spec template, and that template can specify init containers that execute these scripts. See #8

The scripts should be able to operate with and without direct access to the Galaxy backend database.

[innovate-invent]

See #19