feat: Refactors map-simple to use the latest standards.

[willum070]

This PR does the following things:

• Refactors map-simple to use dynamic library loading and the gmp-map element.
• Adds code to show accessing the innerMap element.

[snippet-bot]

Here is the summary of changes.

You are about to add 1 region tag.

• samples/map-simple/index.html:20, tag maps_map_simple_gmpmap

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