Moves various configuration settings from service and utility
packages into the central 'configuration' package. This change
improves maintainability, testability, and allows for more
flexible external configuration of bot behavior.

- Adds new configuration structs and loading logic for Proxy,
  Rate Limiting, and Sentry settings.
- Relocates captcha service endpoints, retry logic constants,
  proxy settings (list, failures, cooldowns), user agents,
  user cleanup interval, and specific API endpoints to the
  configuration.
- Updates services (captcha solvers, http client, proxy manager,
  admin api) to retrieve settings from the global configuration
  object instead of hardcoded constants or environment lookups.
- Decouples Sentry initialization from the core logger setup,
  allowing the logger to be initialized independently.
- Adjusts main startup flow to initialize the logger after
  configuration is loaded, enabling early error reporting via
  standard output before the logger is fully ready.
- Removes the Sentry dependency.
- Cleans up redundant index tags in database models.
- Adjusts database migration logic to rely on AutoMigrate for
  ShardInfo and ProxyStats tables.