Prepare gen3 post launch galaxy setup script

[martenson]

that uses API to set up the

• instance config
• user
• data through manifest (libs, history?)
  • maybe even pre-loads all metadata via a gen3 service.

[martenson]

I think this can wait until https://github.com/galaxyproject/gen3-integration/issues/2 and https://github.com/galaxyproject/gen3-integration/issues/8 are ready.

If the bagit path is not chosen, this will probably depend on https://github.com/galaxyproject/gen3-integration/issues/9 instead.