### Summary of Changes
- Changed the runner configuration for all build jobs in the CI workflow from `ubuntu-latest` to `self-hosted`, ensuring that builds utilize self-hosted infrastructure.
### Expected Results
- Improved build performance and resource management by leveraging self-hosted runners, aligning with the project's infrastructure strategy.
### Summary of Changes
- Introduced a shared setup job in the CI workflow to streamline common steps for building and pushing Docker images.
- Updated individual build jobs for API Gateway, Service Adapters, API Docs, and Frontend to depend on the setup job, ensuring consistent versioning and labeling.
### Expected Results
- Enhanced maintainability and clarity of the CI workflow by reducing redundancy and centralizing setup steps, leading to more efficient Docker image builds.
### Summary of Changes
- Changed the caching strategy in the CI workflow for Docker builds to use the registry for cache references instead of GitHub Actions cache.
- Updated cache-from and cache-to parameters for api-gateway, service-adapters, api-docs, and frontend to improve build performance and consistency.
### Expected Results
- Enhanced Docker build efficiency by utilizing a more reliable caching mechanism, leading to faster build times and reduced resource usage.
### Summary of Changes
- Added a new environment variable `REPO_OWNER` to specify the repository owner in the Docker build workflow.
- Updated image tags in the CI workflow to use `REPO_OWNER` instead of the previous `IMAGE_PREFIX`, ensuring correct tagging for Docker images.
### Expected Results
- Improved clarity and accuracy in Docker image tagging, facilitating better organization and management of images in the registry.
### Summary of Changes
- Introduced a new environment variable `REGISTRY_URL` for the Docker registry in the CI workflow for `docker-build.yml`.
- Updated the registry reference to use `REGISTRY_URL` instead of `REGISTRY` for improved clarity and consistency.
### Expected Results
- Enhanced readability and maintainability of the CI workflow by clearly separating the registry URL and its usage.
### Summary of Changes
- Removed the trailing slash from the Docker registry URL in the CI workflow for `docker-build.yml` to ensure proper formatting.
### Expected Results
- Improved consistency in the Docker registry URL, potentially preventing issues during image builds and deployments.
### Summary of Changes
- Changed the Docker registry URL in the CI workflow from `gitea.example.com` to `https://gittea.kammenstraatha.duckdns.org/` to reflect the new registry location.
### Expected Results
- Ensured that the CI workflow points to the correct Docker registry, facilitating successful image builds and deployments.
