fix 🐛 no such file or dir (os error 2)

[punkbit]

Overview When running the example shell scripts an error is thrown "No such file or directory (os error 2)". These changes provide a fix.

Requirements Checkout the branch and run ./build.sh && ./start.sh

Considered Solutions n/a

Recommended Solution On dfx 0.6.26 the directory is expected to be .dfx/local/canisters/reverse, for that reason a mkdir command creates the desired build directory.

The script now also skips build if the directory already already exists, preceding the call to the canister reverse service.

On sucessful build, the wasm file is now moved instead of copied, and artifacts are cleared from root.

Considerations n/a