feat(perun-propagate): reworked perun-propagate client package

• Perun-propagate client service is now calling Perun API directly, instead of using remctl calls with Kerberos authz.

• Users need to provide configuration in /etc/default/perun-propagate. Following options are available:

  PERUN_PROPAG_USER=perun_propag
  # a script printing user's password on stdout
  PERUN_PROPAG_USER_ASKPASS=/etc/perun/perun_propag.askpass
  PERUN_SERVER=perun-api.e-infra.cz
  PERUN_SLAVE_LOG=/var/log/syslog
  #Timeout in seconds
  TIMEOUT=200

  At least username and password needs to be configured. Of course those credentials must match to existing user in Perun, which must have proper rights to actually force service propagation.

• Updated package major version to 4.

• Updated dependencies.

• Updated year in license.

• Deploy own systemd unit to handle the service.

• Specify shell /bin/sh in deb postfile.

• Updated RPM build.