Godot doesn't really "install", it's just a single executable. To "uninstall" it, just delete the exe.
That said... if you also want to get rid of editor settings and cache data, you should also delete C:\Users\yourlogin\AppData\Roaming\Godot
.
I'm also curious to know how you "installed" it... because there is no official installer, and the Steam version is managed from Steam...