citra_qt: Use the new verify backend; UI changes

Displayed username along with nickname (when they are not identical); Requested and displayed user's avatar; Made the dialog bigger for extended names.

Added a few functions to web_backend (GetImage, GetPlain) to support getting data in multiple content-types.

Added a no_avatar icon for users without avatars.

dist/qt_themes/colorful_dark/style.qrc

@@ -7,6 +7,7 @@
         <file alias="48x48/bad_folder.png">../colorful/icons/48x48/bad_folder.png</file>
         <file alias="48x48/chip.png">../colorful/icons/48x48/chip.png</file>
         <file alias="48x48/folder.png">../colorful/icons/48x48/folder.png</file>
+        <file alias="48x48/no_avatar.png">../qdarkstyle/icons/48x48/no_avatar.png</file>
         <file alias="48x48/plus.png">../colorful/icons/48x48/plus.png</file>
         <file alias="48x48/sd_card.png">../colorful/icons/48x48/sd_card.png</file>
         <file alias="256x256/plus_folder.png">../colorful/icons/256x256/plus_folder.png</file>

dist/qt_themes/default/default.qrc

@@ -18,6 +18,8 @@
 
         <file alias="48x48/folder.png">icons/48x48/folder.png</file>
 
+        <file alias="48x48/no_avatar.png">icons/48x48/no_avatar.png</file>
+
         <file alias="48x48/plus.png">icons/48x48/plus.png</file>
       
         <file alias="48x48/sd_card.png">icons/48x48/sd_card.png</file>

dist/qt_themes/qdarkstyle/style.qrc

@@ -7,6 +7,7 @@
     <file alias="48x48/bad_folder.png">icons/48x48/bad_folder.png</file>
     <file alias="48x48/chip.png">icons/48x48/chip.png</file>
     <file alias="48x48/folder.png">icons/48x48/folder.png</file>
+    <file alias="48x48/no_avatar.png">icons/48x48/no_avatar.png</file>
     <file alias="48x48/plus.png">icons/48x48/plus.png</file>
     <file alias="48x48/sd_card.png">icons/48x48/sd_card.png</file>
     <file alias="256x256/plus_folder.png">icons/256x256/plus_folder.png</file>