Bump SONAME of shared libs from 26 to 27

Also update debian/*.symbols files accordingly.
Remove build-dep to libpq-dev

Upstream does not support PostgreSQL backend anymore so this build
dependency is not needed anymore.
Back to something more dh compliant

This commit introduces many changes:
- Bump debhelper compat level from 7 to 9. Among many things, this
  notably adds automatic binary hardening and multiarch support.
- Deep use of debian/*.{install,manpages,etc} in order to cleanup
  debian/rules to its mimimum.
- Add build-dep to dh-exec for installing perl files in proper
  location.
Remove all lintian overrides

slurm-llnl source package is lintian free.
Split slurm-llnl into base, slurmd and slurmctld

3 new packages to replace slurm-llnl binary package:
  - slurm-llnl-base with all client side commands
  - slurm-llnl-slurmd with slurmd daemon
  - slurm-llnl-slurmctld with slurmctld daemon
Remove perl bs file since empty and not installed
Add native support of systemd

This notably means introduction of native service files for all slurm
daemons.
Enable parallel build
Moved examples in dedicated subdirectory
Adds examples for cgroup configuration in slurmd

2 new examples have been added in slurmd package:

- cgroup.conf: configuration file needed for all plugins that uses
  Linux cgroups. This is a direct copy of etc/cgroup.conf from orig
  tarball without modification.
- cgroup.release_common: release script to cleanup cgroup FS when they
  are empty. Based on etc/cgroup.release_common.example for orig
  tarball but with few fixes from next upstream release and proper
  debian sysconfir.
Remove useless file

Probably a remain from a transient package.
Use globing in libslurm-dev.manpages

It may be usefull to match any future manpage with next upstream
releases.
Update paths in all doc and examples references
New Debian version 14.03.7-0.1