Update system.md by adding NTP details

[axkar]

NTP functionality has been thoroughly verified and the proper documentation is added on:

• Configuring NTP
• Verifying NTP Status
• Verifying NTP Sources

Description

Checklist

Tick relevant boxes, this PR is-a or has-a:

• [ ] Bugfix
  • [ ] Regression tests
  • [ ] ChangeLog updates (for next release)
• [ ] Feature
  • [ ] YANG model change => revision updated?
  • [ ] Regression tests added?
  • [ ] ChangeLog updates (for next release)
  • [ ] Documentation added?
• [ ] Test changes
  • [ ] Checked in changed Readme.adoc (make test-spec)
  • [ ] Added new test to group Readme.adoc and yaml file
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (please detail in commit messages)
• [ ] Build related changes
• [x] Documentation content changes
  • [ ] ChangeLog updated (for major changes)
• [ ] Other (please describe):

[axkar]

A few comments, nothing major, because overall it looks really good!

Thnx for all comment. Hope I have not forgotten anything :)

[axkar]

Great stuff, thanks for hanging in there! 🎉

For future documentation only changes, consider adding the [skip ci] text to the body of your commit message(s), since there's no point in occupying the build and test servers.

Yes, I'll do that :) Thnx