feat: add new-sample.sh script

[oppenheimera]

This script automates the creation of boilerplate for new Google Maps JavaScript samples.

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/new-sample.sh:26, tag $REGION_TAG
• samples/new-sample.sh:39, tag $REGION_TAG
• samples/new-sample.sh:76, tag $REGION_TAG

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