Enables ninja package to generate .deb packages. This patch is only the first step,
as it only generates the aggregate package with all bitcoin* binaries (the PPA currently offers
separate packages for each binary).

This patch is loosely based on contrib/debian/control but the dependencies in that file
appear to be way out of date.

Depends on D5399

Generate the .deb file and try to install it in a fresh VM:

ninja package
dpkg-deb --info bitcoinabc_0.21.1_amd64.deb  # verify basic package information is set correctly

scp bitcoinabc_0.21.1_amd64.deb debian@somevm:~
ssh debian@somevm
sudo dpkg -i bitcoinabc_0.21.1_amd64.deb
sudo apt-get -f install