cli: should give more graceful output on connection issues

[torkelrogstad]

This is the output when trying to connect to a non-accessible location.

❮ cargo run --bin thunder_app_cli -- --rpc-addr 172.105.148.135:6009 balance
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.65s
     Running `target/debug/thunder_app_cli --rpc-addr '172.105.148.135:6009' balance`
Error: client error (Connect)

Caused by:
    0: tcp connect error: Connection refused (os error 61)
    1: Connection refused (os error 61)

Stack backtrace:
   0: std::backtrace_rs::backtrace::libunwind::trace
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1: std::backtrace_rs::backtrace::trace_unsynchronized
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2: std::backtrace::Backtrace::create
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/backtrace.rs:331:13
   3: anyhow::error::<impl core::convert::From<E> for anyhow::Error>::from
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/anyhow-1.0.95/src/backtrace.rs:27:14
   4: <core::result::Result<T,F> as core::ops::try_trait::FromResidual<core::result::Result<core::convert::Infallible,E>>>::from_residual
             at /Users/torkel/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/result.rs:2014:27
   5: thunder_app_cli_lib::Cli::run::{{closure}}
             at ./cli/lib.rs:95:31
   6: thunder_app_cli::main::{{closure}}
             at ./cli/main.rs:7:25
   7: tokio::runtime::park::CachedParkThread::block_on::{{closure}}
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/park.rs:284:63
   8: tokio::runtime::coop::with_budget
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/coop.rs:107:5
   9: tokio::runtime::coop::budget
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/coop.rs:73:5
  10: tokio::runtime::park::CachedParkThread::block_on
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/park.rs:284:31
  11: tokio::runtime::context::blocking::BlockingRegionGuard::block_on
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/context/blocking.rs:66:9
  12: tokio::runtime::scheduler::multi_thread::MultiThread::block_on::{{closure}}
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/scheduler/multi_thread/mod.rs:87:13
  13: tokio::runtime::context::runtime::enter_runtime
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/context/runtime.rs:65:16
  14: tokio::runtime::scheduler::multi_thread::MultiThread::block_on
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/scheduler/multi_thread/mod.rs:86:9
  15: tokio::runtime::runtime::Runtime::block_on_inner
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/runtime.rs:370:45
  16: tokio::runtime::runtime::Runtime::block_on
             at /Users/torkel/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/tokio-1.43.0/src/runtime/runtime.rs:342:13
  17: thunder_app_cli::main
             at ./cli/main.rs:9:5
  18: core::ops::function::FnOnce::call_once
             at /Users/torkel/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
  19: std::sys::backtrace::__rust_begin_short_backtrace
             at /Users/torkel/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/backtrace.rs:152:18
  20: std::rt::lang_start::{{closure}}
             at /Users/torkel/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/rt.rs:194:18
  21: core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/core/src/ops/function.rs:284:13
  22: std::panicking::try::do_call
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panicking.rs:587:40
  23: std::panicking::try
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panicking.rs:550:19
  24: std::panic::catch_unwind
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panic.rs:358:14
  25: std::rt::lang_start_internal::{{closure}}
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/rt.rs:163:24
  26: std::panicking::try::do_call
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panicking.rs:587:40
  27: std::panicking::try
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panicking.rs:550:19
  28: std::panic::catch_unwind
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/panic.rs:358:14
  29: std::rt::lang_start_internal
             at /rustc/99db2737c91d1e4b36b2ffc17dcda5878bcae625/library/std/src/rt.rs:159:5
  30: std::rt::lang_start
             at /Users/torkel/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/std/src/rt.rs:193:5
  31: _main