create docker-compose.yml for ECS `gssmr` devnet

## Issue summary

Create docker-compose.yml file to deploy to ECS a cross client devnet which orchestrates 2 gossamer nodes, and 1 substrate node. Would require a new docker context so adding a new folder to `\devnet` would suffice.

- Ensure metrics for all nodes are flowing to datadog with proper keys as tags.
- Ensure that block production and network messaging is occurring
- Create any issues that halt block production or networking that stop the consistency of the network

## Other Information
- https://github.com/ChainSafe/gossamer/pull/2008
- https://github.com/ChainSafe/gossamer/pull/2096