docs(iroh): add documentations and examples for the `iroh::node::Client` #9623

Job	Run time
Cross Build Only (x86_64-unknown-freebsd)	1m 10s
Android Build Only (aarch64-linux-android)	1m 20s
Build wasm32	26s
Android Build Only (armv7-linux-androideabi)	1m 22s
cargo deny	28s
Checking docs	1m 42s
Checking fmt	7s
check_semver	5m 48s
Checking typos	5s
clippy_check	3m 13s
Cross Test (i686-unknown-linux-gnu)	8m 21s
codespell	5s
Docker Test	17m 28s
Minimal Supported Rust Version	1m 53s
Run network simulations/benchmarks	7m 42s
CI Test Suite / Tests (ubuntu-latest, stable, all)	4m 3s
CI Test Suite / Tests (windows-latest, stable, all, x86_64-pc-windows-msvc)	8m 52s
CI Test Suite / Tests (ubuntu-latest, stable, none)	3m 21s
CI Test Suite / Tests (windows-latest, stable, none, x86_64-pc-windows-msvc)	9m 12s
CI Test Suite / Tests (ubuntu-latest, stable, default)	3m 12s
CI Test Suite / Tests (windows-latest, stable, default, x86_64-pc-windows-msvc)	9m 20s
CI Test Suite / Tests (macOS-arm-latest, stable, all)	5m 26s
CI Test Suite / Tests (macOS-arm-latest, stable, none)	5m 12s
CI Test Suite / Tests (macOS-arm-latest, stable, default)	5m 16s
	1h 45m 4s

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