feat: Migrates the Place Photos sample.

[willum070]

This PR does the following things:

• Migrates the place-photos sample to js-api-samples.
• Makes the sample accessible (wraps thumbnails in button elements, other a11y enhancements).
• Improves visual appearance and UI behavior.

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/place-photos/index.html:7, tag maps_place_photos
• samples/place-photos/index.ts:7, tag maps_place_photos
• samples/place-photos/style.css:6, tag maps_place_photos

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