Add support for multiple connection hops in tx chan-open-try

[romac]

Part of: #3940

Summary

tx chan-open-try

• Replace call to tx_chan_cmd! macro with an inline function on TxChanOpenTryCmd
• In the run() function for TxChanOpenTryCmd, build the reverse channel path, from --dst-chain to --src-chain, by leveraging information available on the existing ChannelEnd that was opened with tx chan-open-init
• Add support for connection hops to Channel::build_chan_open_try_and_send
  • Build multi-hop channel proofs

Tests

• Write integration test for single hop channel

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