Freeze the Tactic Row while Scrolling

[jondricek]

When using the site, it would be useful to be able to scroll down a page that shows an ATT&CK Matrix with the Tactics header frozen to the top. Not sure how difficult this would be to implement, but definitely a feature worth investigating. It would likely be useful for the ATT&CK Navigator as well opening an issue there as well.

Edit: here is the link to the ATT&CK Navigator issue for this: mitre-attack/attack-navigator#404