Console graph color scheme support (#2900)

Add a colorScheme parameter to PromConsole.Graph, to allow using custom colors in console graphs.

web/ui/static/js/prom_console.js

@@ -311,6 +311,9 @@ PromConsole.graphDefaults = {
   yAxisFormatter: PromConsole.NumberFormatter.humanize,
   // Number formatter for y values hover detail.
   yHoverFormatter: PromConsole.NumberFormatter.humanizeExact,
+  // Color scheme to be used by the plots. Can be either a list of hex color
+  // codes or one of the color scheme names supported by Rickshaw.
+  colorScheme: null,
 };
 
 PromConsole.Graph = function(params) {
@@ -420,7 +423,7 @@ PromConsole.Graph.prototype._escapeHTML = function(string) {
 
 PromConsole.Graph.prototype._render = function(data) {
   var self = this;
-  var palette = new Rickshaw.Color.Palette();
+  var palette = new Rickshaw.Color.Palette({scheme: this.params.colorScheme});
   var series = [];
 
   // This will be used on resize.