fix: cleanup dist folder, change README

- move images for README into docs/img
- move libs/* into utils. libs folder is copied into dist by grafana-toolkit
- remove d3-scale-chromatic sources, use it from dependencies
- update compatible versions in README
- update installation info

src/util/d3/d3-scale-chromatic.ts

@@ -0,0 +1,35 @@
+import * as d3 from 'd3';
+import * as d3ScaleChromaticOrig from 'd3-scale-chromatic';
+
+// Add GnYlRd color schema to d3-scale-chromatic
+
+let GnYlRdScheme = new Array(3)
+  .concat(
+    '91cf60ffffbffc8d59',
+    '1a9641a6d96afdae61d7191c',
+    '1a9641a6d96affffbffdae61d7191c',
+    '1a985091cf60d9ef8bfee08bfc8d59d73027',
+    '1a985091cf60d9ef8bffffbffee08bfc8d59d73027',
+    '1a985066bd63a6d96ad9ef8bfee08bfdae61f46d43d73027',
+    '1a985066bd63a6d96ad9ef8bffffbffee08bfdae61f46d43d73027',
+    '0068371a985066bd63a6d96ad9ef8bfee08bfdae61f46d43d73027a50026',
+    '0068371a985066bd63a6d96ad9ef8bffffbffee08bfdae61f46d43d73027a50026'
+  )
+  .map(function(specifier) {
+    var n = (specifier.length / 6) | 0,
+      colors = new Array(n),
+      i = 0;
+    while (i < n) {
+      colors[i] = '#' + specifier.slice(i * 6, ++i * 6);
+    }
+    return colors;
+  });
+
+let GnYlRd = d3.interpolateRgbBasis(GnYlRdScheme[GnYlRdScheme.length - 1]);
+
+let d3ScaleChromatic = {
+  ...d3ScaleChromaticOrig,
+  interpolateGnYlRd: GnYlRd,
+};
+
+export { d3ScaleChromatic };