add smacks and wss to overcome network hickups

Some logger outputs

DevTools failed to load SourceMap: Could not load content for https://noe.fairmeeting.net/libs/app.bundle.min.map: Load canceled due to load timeout

BridgeChannel.js:86 WebSocket connection to 'wss://meet.fairkom.net/colibri-ws/default-id/a5e2b7cfafgsfgsd?pwd=SECRET' failed: Error during WebSocket handshake: Unexpected response code: 200

But we do not see ERR_NETWORK_CHANGED as described here https://community.jitsi.org/t/issue-why-do-some-users-drop-randomly-on-chrome-and-how-to-fix-it-using-xmpp-websocket/87919

To increase tolerance for network blips or disconnects we could also enable smacks (mod_smacks). which “can allow a client to resume a disconnected session, and prevent message loss.” Learn more mod_smacks 22.

Source: https://community.jitsi.org/t/how-to-how-to-enable-websockets-xmpp-websocket-and-smacks-for-prosody/87920

Probably requires update to Prosody 0.11.7: https://community.jitsi.org/t/how-to-how-do-i-update-prosody/72205 (we run 0.11.2)