Add sys-snap tool to Monitoring section

[retalieight]

Thank you for taking the time to work on a PR for Awesome-Sysadmin!

To ensure your PR is dealt with swiftly please check the following:

• Your additions are Free software
• Software your are submitting is not your own, unless you have a healthy ecosystem with a few contributors (which aren't your sock puppet accounts).
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Please take some time to answer the following questions as best you can:

• Why is it awesome?

It allows you to track down processes and users consuming the most CPU and memory between specific times.

• Have you used it? For how long?

For several years, but more when I was working in web hosting. It works on any server not just servers with cPanel.

• Is this in a personal or professional setup?

Personal

• How many devices/users/services/... do you manage with it?

Thousands

• Biggest pros/cons compared to other solutions?

Let's you go back in time to view user and processes resource usage.

• Any other comments about your use case, things you've found excellent, limitations you've encountered... ?