Improve map parsing for compass values (NSEW)

Improve the map parsing and fix bugs with order of lat/long provided to the open street map widget.

It is recommended to use map coordinates with the compass (NSWE) values. For example, this:

center: 35.68406 N, 139.77449 E

(You can use values like 139.77449, 35.68406 but it is imprecise and negative values might be incorrectly parsed.)

Your Svekyll markdown can then look like this:

---
title: "Hello, from Tokyo!"
published: true
date: 2024-03-03
maps:
  function_based_algorithm:
    center: 35.68406 N, 139.77449 E
    index: 0
    zoom: 15
---

Let's see.

<svekyll-map map={maps.function_based_algorithm}/>

Hi there, from Tokyo.