Make CallView use CallFeed

Signed-off-by: Šimon Brandner <simon.bra.ag@gmail.com>

res/css/views/voip/_CallView.scss

@@ -112,6 +112,7 @@ limitations under the License.
     z-index: 30;
     border-radius: 8px;
     overflow: hidden;
+    display: flex;
 }
 
 .mx_CallView_video_hold {

res/css/views/voip/_VideoFeed.scss

@@ -14,11 +14,21 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-.mx_VideoFeed_remote {
-    width: 100%;
-    height: 100%;
+.mx_VideoFeed_voice {
+    // We don't want to collide with the call controls that have 52px of height
+    padding-bottom: 52px;
+    background-color: $inverted-bg-color;
+}
+
+.mx_VideoFeed_video {
     background-color: #000;
-    z-index: 50;
+}
+
+.mx_VideoFeed_remote {
+    flex: 1;
+    display: flex;
+    justify-content: center;
+    align-items: center;
 }
 
 .mx_VideoFeed_local {