The repository, the Python package, the entrypoint and the manifest name all
now agree. `plot` was carried over from the upstream opencv-plot node and no
longer described anything here, so the module, the class and the environment
variables follow the node:
dora_plot/ -> dora_image_view/
dora_plot/plot.py -> dora_image_view/view.py
Plot -> View
PLOT_WIDTH/HEIGHT -> VIEW_WIDTH/HEIGHT
--plot-width/-height -> --view-width/-height
Breaking for anyone wiring `path: dora-plot` or setting PLOT_WIDTH; nothing is
tagged yet.
