Move charts.less into widgets.less

Don't use a separate less file for only two styles

library/Icinga/Web/StyleSheet.php

@@ -24,7 +24,6 @@ class StyleSheet
         'css/icinga/monitoring-colors.less',
         'css/icinga/selection-toolbar.less',
         'css/icinga/login.less',
-        'css/icinga/charts.less',
         'css/vendor/tipsy.css'
     );
 

public/css/icinga/charts.less

@@ -1,11 +0,0 @@
-// {{{ICINGA_LICENSE_HEADER}}}
-// {{{ICINGA_LICENSE_HEADER}}}
-
-/* Add hover effects to chart data */
-.chart-data:hover {
-  opacity: 0.85;
-}
-
-.pie-data:hover {
-  opacity: 0.6;
-}

public/css/icinga/widgets.less

@@ -174,6 +174,15 @@ ul.tree li a.error:hover {
   color: @colorCritical;
 }
 
+/* Add hover effect to chart data */
+.chart-data:hover {
+  opacity: 0.85;
+}
+
+.pie-data:hover {
+  opacity: 0.6;
+}
+
 /* charts should grow as much as possible but never beyond the current viewport's size */
 .svg-container-responsive {
   padding: 1.5em;