[ENH]: Add fancyarrow() as a function to draw single arrows #29826

Problem

Drawing arrows is currently a mess.

1. We have ax.arrow() which uses a fundamentally broken transformation, typically resulting in skewed arrows.
2. There has been ample discussion on replacing arrow() with a more general vector() method Vector #22435
3. We have the recommendation to ax.annotate() with an empty text.

I feel (3.) is quite complicated if you just want to draw an arrow between two points. I therefore suggest to add a method ax.fancyarrow() to replace (3.). It's basically a wrapper for creating a FancyArrowPatch

def fancyarrow(self, ...):
    patch = FancyArrowPatch(...)
    self.add_patch(patch)
    return patch

Rationale:

• The FancyArrowPatch API is capable and clear.
• a wrapper function is justified since user code typically does not explicitly create and add Artists
• The scope is reasonably different from what is discussed for vector() so that it does not overlap with a potential introduction of vector() later
• the name fancyarrow is a bit ... fancy, but we cannot use arrow and since this returns a FancyArrowPatch, fancyarrow seems the best viable name.