In vim 8, bracketed paste mode is supported natively. However, in tmux (2.5), it doesn't seem to work.
This piece of config has been floating around my .vimrc and it seems to make bracketed paste mode work both in and out of tmux.
I offer no support here, I didn't even originally write the code and I'm not familiar enough to know what makes it work. If this doesn't work for you and you can fix it, please submit a PR.
If you don't use tmux, then you don't need this plugin, all you need is vim 8.
Just load the plugin using your normal plugin means