Sprite previewing via dropdowns

[CommanderStorm]

Currently, for selecting a sprite, one has to know the sprites' id.
This is suboptimal as we don't tell users what the options are.

A similar tool, Martin, recently implemented a visual sprite catalog for its dashboard (see maplibre/martin#1956 for inspiration). A similar feature in Maputnik would greatly improve the user experience.

Now, obviously the design language for mapuntk is different - the dialog would not work.
I think if we design it like the following, it could work:

For implementation, this needs to handle:

• Sprites in maplibre can be either sdf or plain.
  Maputnik does not get to choose between these two and render sdf's via the tinysdf-package correctly.
• sprites can be expressions. We should likely not have a dropdown here.
  

I currently don't have the engineering time for this, but might in the future. If someone beats me, feel free ^^

[HarelM]

I think it can make a nice addition, thanks for suggesting!