Lists all the ServiceProvider configuration files found in the configuration folders
        :return:

def list_available_providers(self):
        """
        Lists all the ServiceProvider configuration files found in the configuration folders
        :return: 
        """
        providers = []

        if self.alternative_config_dir:
            for f in os.listdir(os.path.join(self.alternative_config_dir, self.CLOUD_PROVIDERS_DIR)):
                if os.path.splitext(f)[1] in ['.conf', '.json']:
                    try:
                        n = os.path.join(self.alternative_config_dir, self.CLOUD_PROVIDERS_DIR, f)
                        providers.append(ServiceProviderConfiguration(n))
                    except ControllerConfigurationException:
                        pass


        for f in os.listdir(os.path.join(self.default_config_dir, self.CLOUD_PROVIDERS_DIR)):
            if os.path.splitext(f)[1] in ['.conf', '.json']:
                try:
                    n = os.path.join(self.default_config_dir, self.CLOUD_PROVIDERS_DIR, f)
                    providers.append(ServiceProviderConfiguration(n))
                except ControllerConfigurationException:
                    pass

        return providers