Refactor Configuration System to Use Environment Variables

- Removed YAML configuration files for the scraper and web commands, transitioning to an environment-based configuration system.
- Updated configuration structs to utilize `env` tags for loading values from `.env` files, enhancing security and flexibility.
- Implemented reflection-based parsing for environment variables, ensuring type-safe configuration loading.
- Revised documentation to reflect the new configuration approach, including usage examples and best practices for environment variable naming conventions.

cmd/scraper/config.yaml

@@ -1,28 +0,0 @@
-database:
-  mongodb:
-    uri: "mongodb://localhost:27017"
-    name: "tender_management"
-    timeout: 10s
-    max_pool_size: 50
-
-logging:
-  level: "info"
-  format: "json"
-  output: "file"  # stdout, stderr, file
-  file:
-    path: "./logs/scraper.log"
-    max_size: 100      # Max size in MB before rotation
-    max_backups: 5     # Number of backup files to keep
-    max_age: 30        # Max age in days to keep log files
-    compress: true     # Compress rotated files
-
-ted:
-  base_url: "https://ted.europa.eu/packages/daily"
-  timeout: 300s  # Increased to 5 minutes for large files
-  max_retries: 5
-  retry_delay: 10s
-  user_agent: "TenderManagement-TED-Scraper/1.0"
-  max_concurrency: 2  # Reduced to avoid overwhelming the server
-  download_dir: "./tmp/ted_downloads"
-  cleanup_after: 72h
-  scraping_interval: 12h  # Run scraping every 12 hours