wip, repr refactor, moved ctx to ctor

src/mol-plugin/context.ts

src/mol-plugin/state/transforms/representation.ts

src/mol-repr/representation.ts

src/mol-repr/shape/representation.ts

src/mol-repr/structure/complex-representation.ts

src/mol-repr/structure/representation/ball-and-stick.ts

src/mol-repr/structure/representation/carbohydrate.ts

src/mol-repr/structure/representation/cartoon.ts

src/mol-repr/structure/representation/molecular-surface.ts

src/mol-repr/structure/units-representation.ts

src/mol-repr/volume/direct-volume.ts

src/mol-repr/volume/isosurface-mesh.ts

src/mol-repr/volume/registry.ts

src/mol-repr/volume/representation.ts