feat!: remove unneeded logic

[willemneal]

fixes #156

• Removes signing

• Removes parsing the wasm

• Update send_transaction to return the transaction hash and then provide a polling alternative to get the final transaction.

• Removes dependencies on stellar-sdk, soroban-spec, ed25519-dalek,

  • Went from 282 total dependencies to 170, and cold start build times went from 40s to 26s.

• Reduces clap feature set

• Update Client struct to include the Arc<HttpClient> and Arc<str>, allowing the struct to implement clone. Perviously the HttpClient would be constructed each time it was needed of once when Client was constructed.