improving & testing list column type

src/mol-data/db/_spec/table.spec.ts

src/mol-data/db/column.ts

src/mol-io/reader/_spec/cif.spec.ts

src/mol-io/reader/cif/binary/field.ts

src/mol-io/reader/cif/data-model.ts

src/mol-io/reader/cif/schema.ts

src/mol-io/reader/cif/text/field.ts

src/mol-io/writer/cif/encoder.ts

src/mol-model/structure/model/formats/mmcif/assembly.ts

src/mol-util/index.ts