Initial refactor/restructure of nomad's cli.

docs/reference.rst

nomad/cli/__init__.py

nomad/cli/__main__.py

nomad/cli/admin/__init__.py

nomad/cli/admin/admin.py

nomad/cli/admin/clean.py

nomad/cli/admin/run.py

nomad/cli/admin/upload.py

nomad/cli/cli.py

nomad/cli/client/__init__.py

nomad/cli/client/client.py

nomad/cli/client/integrationtests.py

nomad/cli/client/local.py

nomad/cli/client/migration.py

nomad/cli/client/upload.py

nomad/cli/dev.py

nomad/cli/parse.py

nomad/infrastructure.py

nomad/migration.py

setup.py