Refactor authentication configuration in api_client.go and auth.go

[mattdot]

This pull request involves a significant refactor of the configuration and authentication handling in the internal/config and internal/api packages. The main goal is to simplify the configuration structure by moving several fields from ProviderCredentials to ProviderConfig.

Configuration Refactor:

• internal/config/config.go: Moved several fields from ProviderCredentials to ProviderConfig, including TestMode, Urls, TelemetryOptout, Cloud, and TerraformVersion. Updated methods to reflect these changes. [1] [2]

Authentication Updates:

• internal/api/auth.go: Updated various authentication methods to use the new ProviderConfig structure instead of ProviderCredentials. This includes methods like AuthenticateClientCertificate, AuthenticateUsingCli, AuthenticateClientSecret, and AuthenticateOIDC. [1] [2] [3] [4] [5] [6]

Provider Initialization:

• internal/provider/provider.go: Modified the NewPowerPlatformProvider and Configure functions to align with the new ProviderConfig structure. This includes setting fields like TestMode, UseCli, UseOidc, TenantId, ClientId, and others directly on ProviderConfig. [1] [2] [3] [4] [5] [6]

Minor Fixes:

• internal/api/api_client.go: Fixed a conditional check to use client.Config.TestMode instead of client.Config.Credentials.TestMode.