Leverage spritemaps for Flags

[xdrdak]

Currently, Flags has the same implementation/behaviour as Icon, in which loading the base component <Flag> will cause all svgs to be loaded as a chunk. This is normal behaviour, however it's somewhat problematic in this use case since when we're using flags, we usually want all of them loaded at the same time.

What we should be doing is instead of loading all SVGs for Flags, would be to leverage an svg spritemap instead.