Refactored QuantityHistogram.

.gitignore

gui/.gitignore

gui/src/components/api.js

gui/src/components/dft/DFTVisualizations.js

gui/src/components/ems/EMSVisualizations.js

gui/src/components/search/QuantityHistogram.js

gui/src/components/search/Search.js

gui/src/components/search/SearchContext.js

gui/src/config.js

gui/src/searchQuantities.json

nomad/datamodel/dft.py

nomad/gitinfo.py

nomad/metainfo/search_extension.py

nomad/parsing/__init__.py

nomad/search.py