Function validate_application_against_environment_ids 

pub async fn validate_application_against_environment_ids(
    application: &ApplicationToValidate,
    env_ids: &[TargetEnvironmentRef],
    cache_root: Option<PathBuf>,
    app_dir: &Path,
) -> Result<TargetEnvironmentValidation>

Validates all application components against the list of referenced target enviroments. Each component must conform to all environments to pass.

If the return value is Ok(...), this means only that we were able to perform the validation. The caller MUST still check the returned TargetEnvironmentValidation to determine the outcome of validation.

If the return value is Err(...), then we weren’t able even to attempt validation.