Add tx decode/encode subcommands #7163

Job	Run time
check-generated-full-help-docs	44s
fmt	6s
cargo-deny (advisories)	42s
build-and-test (msrv, ubuntu-latest-16-cores, x86_64-unknown-linux-gnu)	1m 12s
cargo-deny (bans)	45s
publish-dry-run	0s
cargo-deny (licenses)	43s
build-and-test (msrv, ubuntu-jammy-16-cores-arm64, aarch64-unknown-linux-gnu)	2m 10s
cargo-deny (sources)	44s
build-and-test (msrv, macos-latest, x86_64-apple-darwin)	2m 59s
build-and-test (msrv, macos-latest, aarch64-apple-darwin)	2m 50s
build-and-test (msrv, windows-latest-8-cores, x86_64-pc-windows-msvc)	3m 27s
build-and-test (latest, ubuntu-latest-16-cores, x86_64-unknown-linux-gnu)	1m 4s
build-and-test (latest, ubuntu-jammy-16-cores-arm64, aarch64-unknown-linux-gnu)	3m 6s
build-and-test (latest, macos-latest, x86_64-apple-darwin)	2m 43s
build-and-test (latest, macos-latest, aarch64-apple-darwin)	2m 4s
build-and-test (latest, windows-latest-8-cores, x86_64-pc-windows-msvc)	2m 33s
complete	1s
	27m 53s

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