feat: add new config command and streamline flags

[emilkje]

This change introduces the concept of configurable settings in the main cwc configuration. The rationale behind this change is to enable more configurable options without polluting the commandline interface with more flags.

The configuration can be managed manually by editing the cwc.yaml config file or by using the cwc config set command.

• Remove --api-version flag as it's now hardcoded The apiVersion config is confusing the end-user where they conflate the azure api version with the openai model version. The azure api version is dictating the capabilities of the API and should therefore be managed by the cwc system and not the end user.
• Add config cmd to the root command for managing CWC configurations
• Update README.md to include configuration management section
• Refactor cmd/cwc.go to remove obsolete flags related to gitignore and git directory exclusion, configuring through cwc config
• Modify error handling in main.go to suppress certain error messages
• Change config file format from JSON to YAML
• Introduce constants for API version and config file properties
• Improve error types with specific checks for template and suppressed errors
• Amend login.go to adapt to the removal of the --api-version flag and use the new config structure
• Remove unnecessary error message handling in config.go related to unmarshalling config data

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