Optimize obsolete connections job (#1885)

* destroy_if_obsolete is now synchronous

* cleanwebsitejob to handle one website per one

* wip delete_obsolete_connections_for_self_and_direct_sources

Co-authored-by: Pierre-André Boissinot <pierreandre.boissinot@noesya.coop>
Co-authored-by: Arnaud Levy <arnaud.levy@noesya.coop>

* wip

* new failed test

* fix

* fix

* clean + delay

* better

* comment

* comment

* comment

* syntax

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Co-authored-by: Pierre-André Boissinot <pierreandre.boissinot@noesya.coop>
Co-authored-by: Arnaud Levy <arnaud.levy@noesya.coop>
Co-authored-by: Arnaud Levy <contact@arnaudlevy.com>