feat: Migrates the event-poi sample to js-api-samples.

[willum070]

This PR makes the following changes:

• Migrates the event-poi sample to js-api-samples.
• Refactors the app to use the gmp-map element and dynamic loading.
• Updates the app to use the New Places API.
• Simplifies the sample by removing directions functionality (too many things distract from the primary use case).

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/event-poi/index.html:7, tag maps_event_poi
• samples/event-poi/index.ts:7, tag maps_event_poi
• samples/event-poi/style.css:6, tag maps_event_poi

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[ReeseJones]

Looks good, I have a few suggestions and questions.