[docs][tests] clarify documents about authentication and filter. Test… #890

Job	Run time
shellcheck	10s
Test container	3m 12s
Test scripts (gantry_cleanup_images_spec.sh)	1m 1s
Test scripts (gantry_common_options_spec.sh)	1m 8s
Test scripts (gantry_filters_spec.sh)	53s
Test scripts (gantry_jobs_spec.sh)	42s
Test scripts (gantry_login_docker_config_spec.sh)	53s
Test scripts (gantry_login_negative_spec.sh)	1m 4s
Test scripts (gantry_login_spec.sh)	1m 12s
Test scripts (gantry_manifest_spec.sh)	57s
Test scripts (gantry_notify_spec.sh)	1m 30s
Test scripts (gantry_parallel_spec.sh)	1m 1s
Test scripts (gantry_rollback_spec.sh)	48s
Test scripts (gantry_service_multiple_spec.sh)	34s
Test scripts (gantry_service_no_running_tasks_spec.sh)	56s
Test scripts (gantry_service_single_spec.sh)	1m 9s
Test scripts (gantry_update_options_spec.sh)	1m 6s
Build and push Docker image	1m 4s
	19m 20s

Provide feedback