Feature sync: support 'request_timeout'

Original: https://github.com/KaymeKaydex/go-vshard-router/issues/117

tnt router call supports new 'request_timeout' option, we should support it too.

See commit: https://github.com/tarantool/vshard/commit/92bcc893e7310ac3ade8da1a72983eea260dbb00