Add documentation to environment_settings on using data_record to manage setttings

[mattdot]

This pull request enhances the documentation and schema descriptions for Power Platform Environment Settings by adding information about accessing and managing additional environment settings stored as Dataverse records.

Documentation updates:

• docs/data-sources/environment_settings.md: Added details on accessing additional environment settings stored in Dataverse and referenced the powerplatform_data_records resource.
• docs/resources/environment_settings.md: Updated to include information on managing additional environment settings using the powerplatform_data_record resource.

Schema description updates:

• internal/services/environment_settings/datasource_environment_settings.go: Enhanced the MarkdownDescription for the EnvironmentSettingsDataSource schema to mention Dataverse records and the powerplatform_data_records resource.
• internal/services/environment_settings/resources_environment_settings.go: Improved the MarkdownDescription for the EnvironmentSettingsResource schema to include information on managing additional settings via the powerplatform_data_record resource.