Update all templates and examples to be compatible with Aysnc circuits

[ymekuria]

Async circuits. Require all smart contract and zkprogram methods to be async https://github.com/o1-labs/o1js/pull/1477

Update all templates and examples.

• [ ] update @methods to be async
• [ ] await to all contract calls await MyContract.myMethod();
• [ ] Use the new @method.returns() decorator to declare a return value from a method