[Canvas] Make it easier to style chart axes

[ryankeairns]

Describe the feature:
Formatting axis labels currently involves some CSS override hacking. It's a common request that would benefit from some specific UI controls to adjust position, rotation, text formatting, etc.

@cqliu1 also noted that "there are a lot more options we could add to the axisConfig function to customize the axes, but idk if we should tackle this work before switching to using Elastic charts"

[elasticmachine]

Pinging @elastic/kibana-canvas

[ryankeairns]

As an example see: https://discuss.elastic.co/t/how-to-rotate-x-tick-label-in-canvas-css/197179

[cqliu1]

Yep, just to add to my comment above, I would say this is blocked by #41714. We are planning to switch to the Elastic charts libary, and as it is now, Elastic charts might not support the some of the customization options we expose in the plot element in Canvas, so instead of adding more flot specific customizations, we should add customization options after the switch to Elastic charts and see what’s available there first.

[cqliu1]

Closing because we're unable to prioritize this work.