attachments parse and resend

[lgg]

relative to #3, #4, #5, #6

• [ ] check how photo resend is realized now
• [ ] check if we can get video source link(youtube, vimeo, etc)
• [ ] check if we can get original link to VK video
• [ ] check how VK video is parsed in Telegram
• [ ] decide what to do with audio(other services(youtube audio, etc), send only text name of the song)
• [ ] decide how to resend documents