moved rcsb code to extensions folder

README.md

src/apps/viewer/index.ts

src/extensions/rcsb/README.md

src/extensions/rcsb/assembly-symmetry/behavior.ts

src/extensions/rcsb/assembly-symmetry/color.ts

src/extensions/rcsb/assembly-symmetry/prop.ts

src/extensions/rcsb/assembly-symmetry/representation.ts

src/extensions/rcsb/assembly-symmetry/ui.tsx

src/extensions/rcsb/graphql/codegen.yml

src/extensions/rcsb/graphql/symmetry.gql.ts

src/extensions/rcsb/graphql/types.ts

src/extensions/rcsb/index.ts

src/extensions/rcsb/validation-report/behavior.ts

src/extensions/rcsb/validation-report/color/density-fit.ts

...tensions/rcsb/validation-report/color/geometry-quality.ts

...ensions/rcsb/validation-report/color/random-coil-index.ts

src/extensions/rcsb/validation-report/prop.ts

src/extensions/rcsb/validation-report/representation.ts

src/mol-model-props/index.ts

src/mol-plugin/behavior/dynamic/custom-props.ts