* feat: Using local.properties to provide API key instead of secure.properties.
* Remove redundant declaration in main AndroidManifest.xml
* Migrate ApiDemos - Kotlin to use local.properties.
* Update README for tutorials.
* Genericize.
* Remove references to secure.properties.
* s/master/main
* chore: Adding samples for V3.
Adding samples for V3 BETA in a new module `app-v3`. These samples are
generated by the `generateV3` Gradle task which runs when the `app`
module is built.
TODOs left:
- [ ] Update README with a note about V3 samples
* Update README and location of secure.properties.
* Using product flavors instead of creating a new module for V3 & GMS.
* Update build workflow to run lint and assemble on all flavor/build types.
* Not using deprecated API.
* Install Android NDK.
* Update license headers.
Previously the Java demo app API key was hard-coded directly in a versioned string resource file, which is dangerous as it's easy to accidentally commit your key into version control.
This PR adds a new process to add your own Google Maps API key for the Java demo app:
1. [Get a Maps API key](https://developers.google.com/maps/documentation/android-sdk/get-api-key)
1. Create a file in the `ApiDemos/java/app` directory called `secure.properties` (this file should *NOT* be under version control to protect your API key)
1. Add a single line to `ApiDemos/java/app/secure.properties` that looks like `MAPS_API_KEY=YOUR_API_KEY`, where `YOUR_API_KEY` is the API key you obtained in the first step
1. Build and run
