Add timetable import command for train schedule v2 #3148

Job	Run time
check_commits	5s
build	3m 50s
check_generated_railjson_sync	19s
check_infra_schema_sync	15s
check_osrd_schema	39s
check_integration_tests	1m 26s
check_railjson_generator	1m 48s
Check final newline	27s
check_core	3m 29s
check_editoast_tests	3m 46s
check_front_rtk_sync	1m 24s
check_editoast_lints	3m 51s
check_editoast_openapi	1m 17s
check_front	1m 42s
check_gateway	1m 30s
integration_tests	4m 53s
	30m 41s

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