Update WASM Oracles docs

[cptartur]

Currently, in the docs of wasm protocol of oracles, we write that package used in connection string must be an asset. This is not required, assets are a QoL function but oracle source can manually be added to target dir (check source code for resolution logic for exact path).

Update the docs to say that the file is searched for in target dir (find specific path) but the recommended approach is to use assets because Scarb will copy the file automatically.