Vertical and horizontal alignment parameters for `align_plots()`

Hey @Yunuuuu First of all, congratulation to this great package and your recent publication! Triggered by our discussion https://github.com/thomasp85/patchwork/issues/452 I was wondering whether `align_plots()` could gain additional `align_horizontal` and `align_vertical` parameters. ``` # align_horizontal = c("left", "right", "center", "justify") # align_vertical = c("bottom", "top", "center", "justify") # left would be something like p1, p2, p3, NULL # right would be something like NULL, p1, p2, p3 # center would be something like NULL, p1, p2, p3, NULL # justify would be something like p1, NULL, p2, NULL, p3 ``` I am curious to hear your thoughts on this. Best Broder