Label the axes, especially to help with (e.g. red-green) colourblindness

[matterhorn103]

Is your feature request related to a problem? Please describe.
Without reading the docs or working it out based on the relative coordinates of atoms, it is not possible to tell which axis is which, despite the axes being helpfully displayed in the bottom-left of the view.

Even once you know which is which, I can imagine it would be difficult for colour-blind people to distinguish the axes based on colour alone, since they are primary colours and in particular both red and green are used.

If it was clearer to the user which axis is which, it would help somewhat to alleviate #1665, as it would be easier to know in advance which axis you want to align to.

Describe the solution you'd like
Simple labels of x, y, and z added to the displayed axes in the matching colour.

They should either:

• be floating just past the end of each of the coloured axes i.e. each arrow points at the respective label, and the mathematical axis runs through the label, but not the drawn axis arrow/cylinder;
• float also on their axis, but to the other side of the origin from the drawn cylinder.

To demonstrate each:

I prefer the first because the chances of two labels overlapping is much higher in the second version.

Both mean that an axis perpendicular to the screen will have its label essentially invisible, but this is ok since the identity of the third axis is always clear via induction. Any other fixed offset position would be obscured sometimes, so this is the most logical compromise. To ensure nothing is ever obscured there would need to be some clever code for avoidance awareness, which seems unnecessary.