vte removed from SDK

[Michael Catanzaro <mcatanzaro gnome org>]

Hi,

vte is going to be adding a new dependency on Boost. After discussion 
in [1], we agreed that it makes sense to remove vte from the GNOME SDK 
so that we don't have to add Boost to the SDK.

This means that if your app depends on vte, you will need to bundle it 
in your flatpak manifest if you are using the master (future 3.36) 
runtime, or your build will fail.

Michael

[1] https://gitlab.gnome.org/GNOME/gnome-build-meta/issues/225