docs(samples): Adding samples for instance from template creation

[m-strzelczyk]

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[m-strzelczyk]

Kurtis, before you point out that the samples should be in separate files - I know :P The refactor is coming sometime next week and I'll reorganize all samples in this repo to follow the new structure. For now I'm keeping it the way it was done so far.

[snippet-bot]

Here is the summary of changes.

You are about to add 3 region tags.

• samples/snippets/sample_instance_from_template.py:15, tag compute_instances_create_from_template
• samples/snippets/sample_instance_from_template.py:16, tag compute_instances_create_from_template_with_overrides
• samples/snippets/sample_instance_from_template.py:59, tag compute_instances_create_from_template_with_overrides

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