Feature proposal: better remote connections in boxes

[Matthias Clasen <matthias clasen gmail com>]

To kick of the feature planning for 3.22, here is a feature that
Zeeshan Ali, Felipe Borges and myself have started to put together:

Make Boxes a first-class client for remote connections

We've started with a feature comparison between boxes and a few remote
connection clients here: https://wiki.gnome.org/Apps/Boxes/Remote

The motivation for this is that we want to have a single, modern and
polished UI for all remote connection needs instead of having a nice
but limited one (boxes already does remote spice and vnc), and a more
fully-featured, but old-school UI (vinagre, remmina, etc...).

I don't expect us to reimplement the feature list 1-to-1, but rather
bring over a reasonable set of features, while leaving the more
obscure options behind. At a minimum, I would want to see rdp support
and a connection setup UI.