shader refactoring: size assignment, matrix-scale, transpose

src/mol-gl/shader/chunks/assign-size.glsl

src/mol-gl/shader/chunks/common.glsl

src/mol-gl/shader/chunks/size-vert-params.glsl

src/mol-gl/shader/mesh.vert

src/mol-gl/shader/points.vert

src/mol-gl/shader/utils/matrix-scale.glsl

src/mol-gl/shader/utils/transpose.glsl