Remove license header from config files and potentially other snippets

From the dev list:

> config files can typically be considered not creative work and therefore not copyrightable. TheASF Source Header and Copyright Notice Policy seems to recognize this in https://www.apache.org/legal/src-headers.html#faq-exceptions

This applies to the `otava.yaml` config, but debatably applies to other code snippets under `examples/`.

Inspect the license header in otava.yaml first, then review the code snippets under examples/ against the Apache Source Header and Copyright Notice Policy. Confirm which files are in scope and remove headers only where the policy supports it; done means the selected config and snippets retain valid content without those headers.

Written by the indexing model from the issue text.