erp5_[credential|xhtml_style]: Drop zocial.css

   It is really not required, so we follow up the same as google oauth.

bt5/erp5_advanced_ecommerce/SkinTemplateItem/portal_skins/erp5_advanced_ecommerce/ERP5Site_getCssRelativeUrlList.py

 return ('jquery/plugin/lightbox/lightbox-0.5.css',
         'jquery/plugin/jqzoom/jqzoom.css',
-        'zocial.min.css',
         'advanced_ecommerce_web.css')

product/ERP5/bootstrap/erp5_xhtml_style/SkinTemplateItem/portal_skins/erp5_xhtml_style/erp5.css.css

@@ -1207,10 +1207,6 @@ fieldset > div.large-gadget {
   height: 85vh;
 }
 
-a.zocial {
-  margin-top: 10px;
-}
-
 body[dir="rtl"] .access_tab_table td > div {
   float: right !important;
 }

product/ERP5/bootstrap/erp5_xhtml_style/SkinTemplateItem/portal_skins/erp5_xhtml_style/zocial.min.css.xml

-<?xml version="1.0"?>
-<ZopeData>
-  <record id="1" aka="AAAAAAAAAAE=">
-    <pickle>
-      <global name="File" module="OFS.Image"/>
-    </pickle>
-    <pickle>
-      <dictionary>
-        <item>
-            <key> <string>__name__</string> </key>
-            <value> <string>zocial.min.css</string> </value>
-        </item>
-        <item>
-            <key> <string>content_type</string> </key>
-            <value> <string>text/css</string> </value>
-        </item>
-        <item>
-            <key> <string>precondition</string> </key>
-            <value> <string></string> </value>
-        </item>
-        <item>
-            <key> <string>title</string> </key>
-            <value> <string>zocial.min.css</string> </value>
-        </item>
-      </dictionary>
-    </pickle>
-  </record>
-</ZopeData>