ci: add individual github workflows for building dockerfiles

[kpango]

• Implemented separate .github/workflows/docker-{target}.yml to build every single Docker image properly inside isolated github workflows instead of relying on the single, buggy, unmaintained docker-base.yml.
• Replaced the hardcoded output parameter type=registry with type=image and push=true with a conditionally configurable parameterized value, allowing workflows and Pull Request validations to not accidentally push and fail without DockerHub credentials.
• Injects missing variable defaults in PR scopes in case secrets are not defined.
• Leverages existing local build makefile commands (e.g., make build_base DOCKER_PUSH=false) to ensure parity with the standard build process of the application logic.

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PR created automatically by Jules for task 13121229839234714668 started by @kpango

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