Add application-level documentation for the push buttons
Feature: https://source.puri.sm/Librem5/use-cases/issues/87
Describe how to access the state of the push buttons.
- Document the API used.
- Cover the flatpak permissions needed.
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Feature: https://source.puri.sm/Librem5/use-cases/issues/87
Describe how to access the state of the push buttons.