fix(documentation): pushpublish docker compose example is broken (#25595)

[dcolina]

Proposed Changes

• This pull request includes the following updates and enhancements to the Docker Compose setup and documentation for the Dotcms Push Publish environment:

  • docker-compose.yml: Unified and configured service aliases.
  • readme.md: Updated with new deployment instructions, endpoint configuration guidance, and environment setup details.

Details

• Unified Docker Compose Manifest: Combined the previously separate Docker Compose manifests for sender and receiver into a single docker-compose.yml file for simplified management.
• Service Aliases Configuration: Configured service aliases for dotcms-sender and dotcms-receiver to facilitate easy referencing between services. Added the alias dotcms-receiver.local and dotcms-sender.local.
• Endpoint Configuration: Provided instructions on using local IP addresses instead of localhost or 127.0.0.1 for endpoint configuration, including commands to find the local IP address (ifconfig for Linux/macOS and ipconfig for Windows).

Additional Info

Related to #25595 (pushpublish docker compose example is broken).