Feature: Interactive graph [as html page]

[dzianis-dashkevich]

Dear contributors,

Thank you for madge, this is a nice and easy-to-use library.
Recently, I forked madge and added an interactive feature for my personal needs.
I decided that this might be helpful for others as well. So here I am.

This feature is highly inspired by: https://github.com/sverweij/dependency-cruiser/blob/develop/src/cli/tools/wrap-stream-in-html.js

Please, check this deployed example based on the video.js open-source project (https://github.com/videojs/video.js):
https://dzianis-dashkevich.github.io/madge-interactive-examples/video-js-graph.html

Controls features (I added it to the README):

Left click selects node(with edges) or edge. Other edges will be dimmed.
Left click out of context(node or edge) resets everything to the initial state.
Right click selects an additional node(with edges) or edge. Has no effect if there are no previously selected items.
Previously selected nodes or edges will be slightly dimmed(but will stay colored).
Escape resets everything to the initial state.

This example was generated by running the following command at the root of the project:
npx madge --interactive interactive-graph.html src/js/video.js

Currently, it is pretty opinionated (eg: colors, controls, etc..), we can discuss potential changes, if you are interested.
Please, just close this PR, If you are not interested in this feature.

Regards,
Dzianis