chore: fixes Wasm path for EnvoyExample, removes detached

[M4tteoP]

• chore(readme): Add Coraza Proxy WASM as WasmPlugin for Istio Guide #233 moved the envoy example into an inner folder, a small fix to the wasm path is needed to properly run the example.
  • A CI test might follow to check that the example correctly loads, but I didn't manage to make it work right now
• Address chore: adds dashboard. #222 (comment) (avoids mage commands in readme)
• Address chore: adds dashboard. #222 (comment) (removes running the example in detached mode by default. It should simplify the usage and reduce the number of commands to just one to have the example running with logs printed)