Added the EMS domain and a new parser skeleton.

dependencies/nomad-meta-info

dependencies/parsers/photoemission

dependencies/parsers/skeleton

dependencies/python_common

nomad/client/local.py

nomad/datamodel/__init__.py

nomad/datamodel/base.py

nomad/datamodel/dft.py

nomad/datamodel/ems.py

nomad/normalizing/normalizer.py

nomad/parsing/__init__.py

nomad/parsing/parser.py

nomad/processing/data.py

ops/scripts/misc.http

tests/data/proc/example_ems.zip

tests/processing/test_data.py

tests/test_api.py

tests/test_datamodel.py

tests/test_parsing.py

tests/test_search.py