Add stroke outline to axis title text

### Feature Proposal

Checked at https://stackoverflow.com/questions/tagged/chart.js, but no info there. We want to add a stroke outline to the y-axis title text(s). It can be done to the tick labels text, why not the axis title text? When we let users select a line color, the axis title is colored the same and sometimes it is too faint, so stroking with a 1 or 2 px dark grey outline is in order. Attempted to create as a plugin, but getting the position of the text is throwing us off.....

### Possible Implementation

Can this be part of the "font" definition?