Create test asset overlay

This is a Work-in-Progress, merged current master and some non-trivial merging issues and stylistic touch-ups need to be applied.

src/features/player/MasonryGrid.jsx

@@ -26,7 +26,7 @@ function MasonryGrid({ sourceUrl, debugSettings, streamingSettings }) {
           />
         </XBlock>
         <XBlock key="log" width={2}>
-          {/*<Log player={player} />*/}
+          <Log player={player} />
         </XBlock>
         {masonrySettings.map(masonryItem => (
           <XBlock key={masonryItem.info.name}>