feat(config): allow config dir to be passed as argument

[sthaha]

This commit now allows default hard-coded config directory to be passed as an argument. This allow quickly changing between different configurations to be stored separately and to switch between them (especially during development).

The commit also

• simplifies global config initialization by ensuring it is initialised at the time kepler's main function is executed and fail with error that step fails.

• It also cleans up use of config object to read CGroup info by creating a realSystem struct that handles this functionality.

[github-actions]

🤖 SeineSailor

Here is a concise summary of the pull request changes:

Summary: This pull request introduces a new --config-dir flag, simplifies global config initialization, and refactors config object usage for CGroup info. It also updates various test files to accommodate these changes.

Key Modifications:

1. Config Directory Flag: A new --config-dir flag allows passing a custom config directory, enabling faster configuration switching during development.
2. Simplified Global Config Initialization: The newAppConfig() signature has been altered to include a BaseDir field, and config is now initialized with BaseDir from appConfig.
3. Refactored Config Object Usage: The realSystem struct has been introduced to clean up config object usage for CGroup info.
4. Test File Updates: Multiple test files have been updated to replace config.GetConfig() with config.Initialize() or config.Instance(), and the ensureConfigInitialized function has been removed.

Impact on Codebase:

• Improved flexibility in configuration management
• Simplified global config initialization
• Enhanced code organization and readability

Suggestions for Improvement:

• Consider adding documentation or comments to explain the purpose and usage of the new --config-dir flag.
• Review the updated test files to ensure they cover all necessary scenarios and edge cases.
• Verify that the realSystem struct is properly utilized throughout the codebase to maintain consistency.