Add linger enablement step, use redirection to save the config

[mateuszstompor]

What has been done:

• Used redirection instead of -o to save service configuration from podman. In the latest version this option is not supported
• I've added step of linger enablement. Without it the web server will not be available after a reboot untill the user logs in
• Code enclosed in snippets
• There was a reference to the user admin, I changed all mentiones to user for consistency