Split QMediaRecorder::setEncodingSettings to separate setters.

It's easier to change only the necessary part of encoding settings.
The settings are applied during the next event loop or before recording
starts.

Change-Id: Ia2b5c93826a302212aa7f79a0c75e4cbaaf1dd7a
Reviewed-by: Ling Hu <ling.hu@nokia.com>
Reviewed-by: Michael Goddard <michael.goddard@nokia.com>

tests/auto/unit/qmultimedia_common/mockmediacontainercontrol.h

@@ -72,12 +72,12 @@ public:
         return m_supportedContainers;
     }
 
-    QString containerMimeType() const
+    QString containerFormat() const
     {
         return m_format;
     }
 
-    void setContainerMimeType(const QString &formatMimeType)
+    void setContainerFormat(const QString &formatMimeType)
     {
         if (m_supportedContainers.contains(formatMimeType))
             m_format = formatMimeType;