Merge branch 'branches/rudder/2.9' into branches/rudder/2.10

Conflicts:
	rudder-agent/SOURCES/check-rudder-agent
Merge branch 'branches/rudder/2.10'

Conflicts:
	rudder-agent/SOURCES/check-rudder-agent
Fixes #4666: Change the dependencies of the packages to ease a per-service installation
Merge pull request #275 from Kegeruneku/ust_4654/int/4666_segment_packages_into_idependent_entities

Fixes #4666: Change the dependencies of the packages to ease a per-servi...
Fixes #4776: Add rudder-server-root as a dependency on rudder-server-root
Merge pull request #309 from Kegeruneku/ust_4654/int/4776_add_rudder_reports_as_a_dep_on_rudder_server_root

Fixes #4776: Add rudder-server-root as a dependency on rudder-server-roo...
Fixes #4738: Prevent a stray warning from occurring while starting jetty if the Rudder plugins directory is missing