Rewrite packaging to use `dh` sequencer and remove the need for `fakeroot`

Rewrite packaging to use `dh` sequencer and remove the need for `fakeroot`

Known issues:
 * Upstream's build system does not insert a build-id into libauthbind.so.1.0
   triggering a warning from `dh_strip`. This means the -dbgsym package
   does not include debug symbols for that library. It still provides
   debug for other binaries such `usr/lib/authbind/helper`, so still
   a net improvement. Fixing this would probably require patching
   upstream's Makefile or manually compiling the library. However, it was
   not a "low-enough" hanging fruit that I fixed as it.

Remarks on the diffoscope delta for the `.deb`:
 * New control files: md5sums, shlibs, and triggers. These match the
   expected outcome of (now) using `dh_md5sums` and `dh_makeshlibs`.
 * Content deltas of ELF binaries. This is expected. The strip process
   now also removes `.comment`. Additionally, debug links are inserted
   into the binaries. No delta in the instructions/binary code.
 * The Debian changelog is now trimmed (size delta), which is expected
   with dh_installchangelogs (as of `debhelper/13.10`).
 * Delta of symlinks mode in data.tar (g+w): Benign delta. The mode
   is not relevant for the symlink and was caused by tar preserving
   a recursive `chmod g-w` that is now removed (replaced by `dh_strip`)

Closes: #1086628