factored webgl object out of props into a repr ctx

src/apps/canvas/component/representation.tsx

src/apps/canvas/structure-view.ts

src/apps/canvas/volume-view.ts

src/apps/structure-info/volume.ts

src/mol-geo/geometry/geometry.ts

src/mol-geo/util/marching-cubes/algorithm.ts

src/mol-math/geometry/gaussian-density.ts

src/mol-math/geometry/gaussian-density/gpu.ts

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

src/mol-model/structure/structure/unit/gaussian-density.ts

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

src/mol-repr/index.ts

src/mol-repr/shape/index.ts

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

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

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

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

src/mol-repr/structure/visual/carbohydrate-link-cylinder.ts

src/mol-repr/structure/visual/carbohydrate-symbol-mesh.ts

...ol-repr/structure/visual/cross-link-restraint-cylinder.ts