Restrict trackpad scrolling in grid to a single axis

[dsmmcken]

@alexbassy is there a way to lock scrolling in a data grid to a given axis rather than being able to scroll X & Y? e.g. for only horizontal scrolling. if not, this would be a really useful feature!

Slack user reports having a trackpad, and wanting to scroll grid in strictly one axis, instead of getting diagonal deltas, when attempting to scroll only horizontally.

Note: For mouse scroll wheels, we replicate the OS feature of holding shift to scroll on the horz. axis. Maybe there's something like that we could do. I am not aware of any OS conventions for this.