Refactoring custom model props

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

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

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

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

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

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

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

src/servers/model/test.ts