Update tools comparison in website

[szymontrocha]

It would be good to update https://www.perfsonar.net/about/comparison-with-other-monitoring/ with a few more features to compare and verify others are still relevant:

• firewalls. E.g. RIPE Atlas can be plugged in anywhere and no firewall changes are required
• Ease of setup. Atlas is literally plug and play.

Originally suggested by Tim Chown

[laeti-tia]

We could also add other tools to compare against. There have been suggestions recently to compare perfSONAR to ThousandsEyes and to NetBeez.

And comparison should add licence type and price.

[mfeit-internet2]

The comparison page on the new site is driven by data and should be easy to expand and modify. Here's what the source for the page looks like: https://raw.githubusercontent.com/mfeit-internet2/jekyll-test/gh-pages/pages/gtk/comparison.md

Additions are encouraged.