wip, refactoring mmCIF parsing for better IHM model support

src/apps/structure-info/model.ts

src/mol-data/db/table.ts

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

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

src/mol-model/structure/model/formats/mmcif/bonds/comp.ts

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

src/mol-model/structure/model/properties/coarse/hierarchy.ts

...mol-model/structure/model/properties/utils/coarse-keys.ts