[VkBridge] Several improvements (#1802)
[VkBridge] Several improvements (#1802)

* Improved post author computation
* Show repost sources
* Handle second copy quote
* Fixed incorrect image uri's
sebsauvage/rss-bridge,ORelio/rss-bridge,Riduidel/rss-bridge,ORelio/rss-bridge,RSS-Bridge/rss-bridge,kranack/rss-bridge,Riduidel/rss-bridge,ORelio/rss-bridge,Riduidel/rss-bridge,kranack/rss-bridge,RSS-Bridge/rss-bridge,kranack/rss-bridge,kranack/rss-bridge,RSS-Bridge/rss-bridge