Add WASM examples

[6r1d]

At this point, we should add the usage examples and the API code.

According to Alexander Strokov, we have a JavaSDK test, "Wasm trigger mints NFT for every user": https://github.com/hyperledger/iroha-java/blob/027c16853429616f0682433824a77b702ead8029/modules/client/src/test/kotlin/jp/co/soramitsu/iroha2/TriggersTest.kt#L236

There are also some rudimentary examples for Rust in client/tests/integration/smartcontracts according to Vladimir