Add workaround for plotly.js for a wont-fix bug in Firefox

See also: https://bugzilla.mozilla.org/show_bug.cgi?id=756985

plotly-workaround-for-firefox/README

@@ -0,0 +1,12 @@
+This is the official plotly.min.js of the plotly.js
+library version 1.58.5 with the following fix:
+
+return (
+  // Workaround for a bug in firefox, see https://bugzilla.mozilla.org/show_bug.cgi?id=756985
+  t.getCTM() === null ? 0 : t.getCTM().e
+)+t.getBBox().width
+
+This fix has been incorporated directly into the
+minified build, as it doesn't make a lot of sense
+to file a proper pull request to upstream for such
+an old version of the library.

webpack.config.js

@@ -55,7 +55,7 @@ module.exports = {
         to: './vendor/webcomponentsjs/custom-elements-es5-adapter.js',
       },
       {
-        from: 'node_modules/plotly.js/dist/plotly.min.js',
+        from: 'plotly-workaround-for-firefox/plotly.min.js',
         to: './vendor/plotly.js/plotly.min.js',
       },
     ]),