Allow adjustments to blinking text-editor cursor

[andreas-stefik]

There's a user request to be able to adjust the following properties of the cursor:

1. Height
2. Width
3. Color
4. Blinking speed
5. Whether it is up and down or left and right or both

While I've assigned this one to William, in practice this is not a feature for this release. We could consider it for blocks, however, as this feature needs to change anyway in the new design.