qt: make receive coins tab look more consistent with send coins tab

Use a GridLayout instead of a FormLayout. This makes the alignment
of the labels consistent between the tabs.

src/qt/forms/receivecoinsdialog.ui

@@ -12,15 +12,15 @@
   </property>
   <layout class="QVBoxLayout" name="verticalLayout">
    <item>
-    <layout class="QFormLayout" name="formLayout">
-     <property name="fieldGrowthPolicy">
-      <enum>QFormLayout::AllNonFixedFieldsGrow</enum>
-     </property>
+    <layout class="QGridLayout" name="gridLayout">
      <item row="3" column="0">
       <widget class="QLabel" name="label">
        <property name="text">
         <string>&amp;Amount:</string>
        </property>
+       <property name="alignment">
+        <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+       </property>
        <property name="buddy">
         <cstring>reqAmount</cstring>
        </property>
@@ -44,6 +44,9 @@
        <property name="text">
         <string>&amp;Label:</string>
        </property>
+       <property name="alignment">
+        <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+       </property>
        <property name="buddy">
         <cstring>reqLabel</cstring>
        </property>
@@ -61,6 +64,9 @@
        <property name="text">
         <string>&amp;Message:</string>
        </property>
+       <property name="alignment">
+        <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+       </property>
        <property name="buddy">
         <cstring>reqMessage</cstring>
        </property>
@@ -99,6 +105,19 @@
      </item>
     </layout>
    </item>
+   <item>
+    <spacer name="verticalSpacer">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="sizeHint" stdset="0">
+      <size>
+       <width>20</width>
+       <height>40</height>
+      </size>
+     </property>
+    </spacer>
+   </item>
    <item>
     <layout class="QHBoxLayout" name="horizontalLayout">
      <item>