refactoring CIF exporter

src/apps/cif2bcif/converter.ts

src/mol-io/writer/cif.ts

src/mol-model-props/pdbe/structure-quality-report.ts

src/mol-model-props/rcsb/symmetry.ts

src/mol-model/structure/export/categories/atom_site.ts

...ol-model/structure/export/categories/modified-residues.ts

...-model/structure/export/categories/secondary-structure.ts

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

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

...-model/structure/model/formats/mmcif/bonds/struct_conn.ts

src/mol-model/structure/model/properties/custom/residue.ts

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

src/perf-tests/cif-encoder.ts

src/servers/model/preprocess/converter.ts

src/servers/model/preprocess/preprocess.ts

src/servers/model/server/query.ts

src/servers/volume/server/query/encode.ts