Change CLAPI doc to use centreon user instead of root

doc/en/api/clapi/engine_management.rst

doc/en/api/clapi/import_export.rst

doc/en/api/clapi/index.rst

doc/en/api/clapi/objects/acl.rst

doc/en/api/clapi/objects/acl_action.rst

doc/en/api/clapi/objects/acl_group.rst

doc/en/api/clapi/objects/acl_menu.rst

doc/en/api/clapi/objects/acl_resource.rst

doc/en/api/clapi/objects/broker_cfg.rst

doc/en/api/clapi/objects/commands.rst

doc/en/api/clapi/objects/contact_groups.rst

doc/en/api/clapi/objects/contacts.rst

doc/en/api/clapi/objects/dependencies.rst

doc/en/api/clapi/objects/downtimes.rst

doc/en/api/clapi/objects/host_categories.rst

doc/en/api/clapi/objects/host_groups.rst

doc/en/api/clapi/objects/hosts.rst

doc/en/api/clapi/objects/instances.rst

doc/en/api/clapi/objects/ldap_servers.rst

doc/en/api/clapi/objects/nagios_cfg.rst