Added example for the DS18B20

[pedrominatel]

ESP-BSP Pull Request checklist

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• [ ] Version of modified component bumped
• [ ] CI passing

Change description

This PR adds a simple example of how to read the DS18B20. This example was used during a presentation to show how to use the components and BSP.

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[pedrominatel]

LGTM!

To fix the build issue, I think you need to add a rule in .build-test-rules.yml to only build the example if the chip has RMT:

components/ds18b20:
  disable:
    - if: SOC_RMT_SUPPORTED != 1
      reason: Onewire component depends on RMT peripheral

and please clean up commit history before merging.

Can you kindly take a look, @tore-espressif? Many thanks!