Also apply following changes to Java version:
* Refactor variables to remove Hungarian notation
* Remove redundant cast for TextView
* Normalize instance variable names
* Normalize capitalization of activity title in UI list
* Use lambda (requires Java 8 support)
* Support Java 8 features (for all Java demos) via build.gradle
* 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
* Update ApiDemos/java to latest Maps SDK for Android
* Update ApiDemos/kotlin to latest Maps SDK for Android
* Update tutorials/CurrentPlaceDetailsOnMap to new Places SDK for Android
* Update tutorials/MapWithMarker to latest Maps SDK for Android
* Update tutorials/Polygons to latest Maps SDK for Android
* Update tutorials/StyledMap to latest Maps SDK for Android
* Update README with better instructions for API key
