Update welcomepage with a shiny background

I introduced some graphical details in the background
that replaces the gradient. I also fixed the foreground
square a bit to get rid of the blurry line at the bottom.

Reviewed-by: danimo

src/plugins/welcome/welcome.qrc

@@ -1,6 +1,6 @@
 <RCC>
-    <qresource prefix="/welcome" >
+    <qresource prefix="/welcome">
-       <file>images/btn_26.png</file>
+        <file>images/btn_26.png</file>
         <file>images/btn_26_hover.png</file>
         <file>images/btn_27.png</file>
         <file>images/btn_27_hover.png</file>
@@ -19,5 +19,6 @@
         <file>images/combobox_arrow.png</file>
         <file>images/arrow-left.png</file>
         <file>images/arrow-right.png</file>
+        <file>images/welcomebg.png</file>
     </qresource>
 </RCC>

src/plugins/welcome/welcomemode.ui

@@ -76,13 +76,13 @@ QToolButton:pressed, QPushButton:pressed{
    <item>
     <widget class="QWidget" name="gradientWidget" native="true">
      <property name="styleSheet">
-      <string notr="true">
+      <string notr="true">/*
 #gradientWidget {
   background-color: qlineargradient(spread:pad, x1:0.5, y1:0, x2:1.0, y2:1, stop:0 rgba(240, 240, 240, 255), stop:1 rgba(200, 200, 200, 255));
 }
-
+*/
 #gradientWidget {
-    border-image: url(:/core/images/welcomebg.png) 4;
+    border-image: url(:/welcome/images/welcomebg.png) 0;
 }
 </string>
      </property>
@@ -119,8 +119,8 @@ QToolButton:pressed, QPushButton:pressed{
         <property name="styleSheet">
          <string notr="true">#mainFrame {
     border-image: url(:/welcome/images/background_center_frame.png);
-    border-width: 4;
+    border-width: 2;
-	padding:-3;
+	padding:-1;
     padding-bottom:20	;
 }