Added the possibility to use custom schemas in apps and search.

docs/oasis/apps.md

docs/oasis/customize.md

docs/reference/config.md

examples/metainfo/metainfo_metrics.py

gui/src/components/Quantity.js

gui/src/components/UserdataPage.js

gui/src/components/archive/metainfo.js

gui/src/components/conftest.spec.js

gui/src/components/dataset/DatasetPage.js

gui/src/components/datatable/Datatable.js

gui/src/components/nav/Routes.js

gui/src/components/plotting/PlotScatter.js

gui/src/components/search/Filter.js

gui/src/components/search/FilterRegistry.js

gui/src/components/search/FilterSummary.js

gui/src/components/search/FilterSummary.spec.js

gui/src/components/search/SearchBar.js

gui/src/components/search/SearchContext.js

gui/src/components/search/SearchPage.spec.js

gui/src/components/search/conftest.spec.js