Radical.pilot

- Add fallback for ssh tunnel on ifconfig-less nodes
- cleanup old resources
- removed OSG leftovers
- updating test cases
- fix recursive flag


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- fix shell escaping for task arguments


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- amarel cfg


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- fixed pilot staging for input directories
- clean up configs
- disabled `os.setsid` in `Popen` executor/spawner (in
`subprocess.Popen`)
- refreshed module list for Summit
- return virtenv setup parameters
- Support for :py:mod:`radical.pilot.X` links. (eirrgang)
- use local virtual env (either venv or conda) for Summit


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- adapt flux integration to changes in flux event model
- fix a merge problem on flux termination handling


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- artifact upload for RA integration test
- encapsulate kwargs handling for Session.close().
- ensure state updates
- fail tasks which can never be scheduled
- fixed jsrun resource_set_file to use `cpu_index_using: logical`
- separate cpu/gpu utilization
- fix error handling in data stager
- use methods from the new module `host` within RU (\>=1.6.7)


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