Since acrn-tools are not built when creating a release build, there are no
tool binaries to be installed. Generate the required debian/acrn-tools.install
file on the fly whenever a debug build is requested. This keeps this file
empty on a release build avoiding the resulting build errors about missing
files.
Additionally a package specific README.Debian file is added to explain this
behavior. It will be installed according to Debian packaging guidelines
at /usr/share/doc/acrn-tools/README.Debian.
Tracked-On: #8257
Signed-off-by: Helmut Buchsbaum <helmut.buchsbaum@opensource.tttech-industrial.com>