Enable explicit API mode and add Binary Compatibility Validator

[MGaetan89]

Description

This PR enforces some good practices for Kotlin libraries. The complete guide is available on Kotlin's website.

Changes made

• Enable Explicit API mode. This forces us to declare the visibility of every member, as well as the type of public members.
• Add Binary Compatibility Validator. This generates a dump of the library's public API and complains when it changes.
• Update the GitHub Workflow to check API dumps and update them if needed.
• Fix explicit mode errors.

[github-actions]

Code Coverage

Overall Project	39.17%	🟢

File	Coverage
MediaRouteButtonViewModel.kt	90.91%	🟢
MediaRouteButton.kt	82.22%	🟢
MediaRouteControllerDialog.kt	0%	🟢
MediaRouteChooserDialog.kt	0%	🟢