Resolve dependencies with dpkg-shlibdeps

[eggerk]

This replaces the dependency resolving from ldd to use dpkg-shlibdeps instead, as suggested in #170 and #178.

As an example of this change, the old ldd-based dependencies were resolved as:

 Depends: libkrb5-3 (>= 1.17), libc6 (>= 2.31), libkeyutils1 (>= 1.6), libnorm1 (>= 1.5.8+dfsg2), libgssapi-krb5-2 (>= 1.17), libpgm-5.2-0 (>= 5.2.122~dfsg), libkrb5support0 (>= 1.17), libstdc++6 (>= 10.3.0), libzmq5 (>= 4.3.2), libsodium23 (>= 1.0.18), libcom-err2 (>= 1.45.5), libk5crypto3 (>= 1.17)

While the new approach resolves this to simply:

Depends: libc6 (>= 2.18), libzmq5 (>= 4.0.1+dfsg)

Some notes:

• As noted by @H-M-H in #170, dpkg-shlibdeps requires the existance of a debian/control file which can even be empty. Furthermore, it's seemingly not even necessary that the executable is anywhere near the control file.

[kornelski]

Thank you