[erp5_web_renderjs_ui] Start using less mixin to reduce duplication

bt5/erp5_web_renderjs_ui/PathTemplateItem/web_page_module/rjs_gadget_erp5_css.xml

@@ -230,7 +230,7 @@
             </item>
             <item>
                 <key> <string>serial</string> </key>
-                <value> <string>952.10134.56146.36130</string> </value>
+                <value> <string>952.12715.63499.47547</string> </value>
             </item>
             <item>
                 <key> <string>state</string> </key>
@@ -248,7 +248,7 @@
                     </tuple>
                     <state>
                       <tuple>
-                        <float>1467039078.03</float>
+                        <float>1467193792.99</float>
                         <string>UTC</string>
                       </tuple>
                     </state>

bt5/erp5_web_renderjs_ui/SkinTemplateItem/portal_skins/erp5_web_renderjs_ui/erp5css.less.txt

@@ -78,9 +78,17 @@
 
 
 
+///////////////////////////////////////////////
+// Extend
+///////////////////////////////////////////////
 
-
-
+.hide_text(@width: 3em) {
+  // https://css-tricks.com/forums/topic/hide-text-but-not-the-before-pseudo-class/
+  width: @width;
+  overflow: hidden;
+  text-indent: -9999px;
+  white-space: nowrap;
+}
 
 
 
@@ -531,11 +539,7 @@ div[data-gadget-scope='panel'] {
 
     button, a {
 
-      // https://css-tricks.com/forums/topic/hide-text-but-not-the-before-pseudo-class/
-      width: 3em;
-      overflow: hidden;
-      text-indent: -9999px;
-      white-space: nowrap;
+      .hide_text();
       background-color: #252525;
 
       &::before {
@@ -670,11 +674,7 @@ div[data-gadget-scope='editor_panel'] {
 
     button, a {
 
-      // https://css-tricks.com/forums/topic/hide-text-but-not-the-before-pseudo-class/
-      width: 3em;
-      overflow: hidden;
-      text-indent: -9999px;
-      white-space: nowrap;
+      .hide_text();
       background-color: #252525;
 
       &::before {
@@ -739,10 +739,7 @@ div[data-gadget-scope='header'] .ui-header {
       // Default size
       width: 8em;
       @media @smartphone {
-        width: 3em;
-        overflow: hidden;
-        text-indent: -9999px;
-        white-space: nowrap;
+        .hide_text();
       }
 
       &::before {
@@ -1104,10 +1101,7 @@ div[data-gadget-scope='erp5_searchfield'] {
       }
 
       @media @smartphone {
-        width: 2em;
-        overflow: hidden;
-        text-indent: -9999px;
-        white-space: nowrap;
+        .hide_text(@width: 2em);
       }
 
       &::before {
@@ -1287,10 +1281,7 @@ div[data-gadget-scope='erp5_searchfield'] {
         }
 
         @media @smartphone {
-          width: 2em;
-          overflow: hidden;
-          text-indent: -9999px;
-          white-space: nowrap;
+          .hide_text(@width: 2em);
         }
 
         &::before {