added invariant bounding sphere, instance bounding sphere to helper

src/mol-canvas3d/helper/bounding-sphere-helper.ts

src/mol-geo/geometry/direct-volume/direct-volume.ts

src/mol-geo/geometry/lines/lines.ts

src/mol-geo/geometry/mesh/mesh.ts

src/mol-geo/geometry/points/points.ts

src/mol-gl/_spec/renderable.spec.ts

src/mol-gl/_spec/renderer.spec.ts

src/mol-gl/renderable/direct-volume.ts

src/mol-gl/renderable/schema.ts

src/mol-gl/renderable/util.ts