fix: add new optimized centering and zoom for countries data prop to …

[mcstover]

…KvMap. Does what it says in the prop description and adds tested utility methods that can probably be used independently

• Automatically compute optimal map center and zoom level based on countriesData distribution.
• This is an alternative to setting lat/long/zoomLevel directly.
• Requires: countriesData prop must contain data with lat/long coordinates.
• Note: Explicit lat/long props will override the computed center when provided.
• When enabled, zoomLevel prop is ignored in favor of the computed optimal zoom.

Single Country:

Countries Close to one another: