Changes

utils/osmo-install-dbg-pkgs: new script

Add a script that automatically figures out the debug packages for
installed Osmocom programs, libraries and their dependencies, and
installs them.

Install the script via debian/rules instead of
debian/libosmocore-utils.install, so it is possible to install to
/usr/bin/osmo-install-dbg-pkgs (without ".py" at the end).

Related: SYS#7224
Change-Id: I903cef0a3e358701d14dcf1980fe0f8d5d5b4d62