release: Remove KDE from dvd1.iso

Prior to this commit, we were shipping 2155 MB of packages (from the
ports tree, not counting pkgbase) on dvd1.iso.  Due to the amount of
space required by shipping pkgbase packages *and* distribution sets
on the DVD images, we only have 1696 MB available if we want to fit
into the 4.7 GB limit for DVDs.  Many users have indicated that this
is indeed important.

It is practically impossible to hit this target without removing KDE;
while KDE and its dependencies narrowly fit (1550 MB), we exceed the
limit as soon as we include either of freebsd-doc-all or gnome.  While
we would pick KDE over GNOME (surveys regularly indicate that KDE is
the more widely used of the two), we believe that documentation is the
most important thing to include.

Since removing KDE leaves a bit of extra space, add editors/emacs and
editors/vim.  This takes the 15.0 amd64 dvd1.iso up to 4.689 GB. [1]

Requested by:	adamw [1]
MFC after:	immediately (for 15.0-RC3)
Differential Revision:	https://reviews.freebsd.org/D53800

release/scripts/pkg-stage.sh

@@ -15,6 +15,8 @@ export PORTSDIR="${PORTSDIR:-/usr/ports}"
 
 _DVD_PACKAGES="
 devel/git@lite
+editors/emacs
+editors/vim
 misc/freebsd-doc-all
 net/mpd5
 net/rsync
@@ -29,7 +31,6 @@ sysutils/tmux
 www/firefox
 www/links
 x11/gnome
-x11/kde
 x11/sddm
 x11/xorg
 x11-wm/sway