Image pasting functionality into rooms

[b401]

Hey there,

I've gone ahead and implemented image paste functionality into gomuks. It seems like the better way to do this would get it done through mautrix instead but this is so far the working solution I've come up with.

I wasn't able to get Paste() or OnPasteEvent() to register my inputs so this is why I've added it to OnKeyEvent()

Thanks a lot for all your work on gomuks!

[AlexBocken]

Thanks so much for developing this PR, I've been using your branch for the last few weeks without any issues. Since using tulir's Whatsapp bridge ( https://github.com/mautrix/whatsapp ) I've come across an error which only persists in gomuks (Element for example does not have this error).

On pasting into Whatsapp-bridged chats I get the error:

Would you be able to insert a media type as well such that image pasting works for Whatsapp bridged chats as well?

Let me know if you need more information from me to resolvethis issue.