i18n: Make topics, SLAs, lists, list items translatable

include/class.dynamic_forms.php

include/class.forms.php

include/class.list.php

include/class.sla.php

include/class.topic.php

include/staff/dynamic-list.inc.php

include/staff/helptopic.inc.php

include/staff/helptopics.inc.php

include/staff/slaplan.inc.php

include/staff/templates/dynamic-field-config.tmpl.php

include/staff/templates/dynamic-form.tmpl.php

include/staff/templates/list-item-properties.tmpl.php

include/staff/ticket-open.inc.php