Set up automated tests for the Android Studio plugin

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Manually testing if the plugin works take time, requires an existent Android project and might miss some cases.

Automated tests ensure that the plugin covers all test cases and is working correctly.

If a CI/CD pipeline is implemented, the automated tests can be run when commits are pushed and inform if a change makes a test to fail, thus ensuring that PRs will not break the plugin.

Refer to the IntelliJ Testing Plugins and Testing a Custom Language Plugin doc pages for more details.