Allow widgets to autoplay media

This is useful for e.g. webcam streams in widgets.

Signed-off-by: Willem Mulder <willemmaster@hotmail.com>

Author: 14mRh4X0r

src/components/views/elements/AppTile.js

@@ -544,7 +544,7 @@ export default class AppTile extends React.Component {
 
         // Additional iframe feature pemissions
         // (see - https://sites.google.com/a/chromium.org/dev/Home/chromium-security/deprecating-permissions-in-cross-origin-iframes and https://wicg.github.io/feature-policy/)
-        const iframeFeatures = "microphone; camera; encrypted-media;";
+        const iframeFeatures = "microphone; camera; encrypted-media; autoplay;";
 
         const appTileBodyClass = 'mx_AppTileBody' + (this.props.miniMode ? '_mini  ' : ' ');