Make it easier to find how to run ngrok in the background

[TheConcierge]

Problem

This quick start guide is great at getting you up and running when you are actively interacting with your terminal. However, the next logical step is: how do I make the ngrok agent run persistently without keeping my terminal open forever. We do have docs about "daemonizing", but it's a hard page to find, especially if the user doesn't have the exact perfect vocabulary.

Solutions

• add links to the end of the quick start guide for persisting ngrok (docker, systemd service, detach tmux session (jk), etc)
• rename the "deamonizing" page to something more discoverable by the average person