Switch from `fib` to basic account example in the source code for `cargo miden new` project

[Denys Zadorozhnyi]

After #146 is implemented and #182 merged.

See a WIT-based code for example in

compiler/tests/rust-apps-wasm/wit-sdk/basic-wallet/src/lib.rs

Lines 20 to 29 in 581f639

 impl Guest for Component { 
     fn receive_asset(asset: CoreAsset) { 
         add_asset(asset); 
     } 
  
     fn send_asset(asset: CoreAsset, tag: Tag, recipient: Recipient) { 
         let asset = remove_asset(asset); 
         create_note(asset, tag, recipient); 
     } 
 }