Fix the gradle build configuration for the Android platform

[m4gr3d]

Refactor needed following #66242

[akien-mga]

I don't know what gradle needs but I think it would be clearer if we followed the same structure as in scons, so:

supportedFlavors = ["editor", "template_debug", "template_release"]
supportedBuildTypes = ["regular", "dev"]  // In SCons it's just a boolean, so could be the same here if that works.

dev_build=yes can now be used with any target so target=template_release dev_build=yes is also a valid use case (gives template_release.dev lib). It's not a particularly useful combination but it's IMO better if gradle follows the same logic of having only three targets and then a bool for dev_build.

[m4gr3d]

The new build model unfortunately doesn't match with Gradle's build layout.
Gradle has the concept of build types and product flavors:

• A product flavor is a different version of the project (e.g: demo version vs full version). This aligned somewhat better with the previous build architecture where tools=no corresponded to the template flavor and tools=yes corresponded to the editor flavor
• A build type on the other hand mapped to our previous concept of target and is used configure the build configuration (debug symbols, optimization, etc)

With the new build model, we still have two product flavors ('editor' and 'template') and still three build types ('dev', 'release_debug' and 'release'), so the gradle build model is still valid, we just need to update the mapping when we generate the scons command.

[m4gr3d]

The build types are also shared across the project modules, while the flavors are linked:

• The app module maps to the template flavor
• The editor module maps to the editor flavor
• As a dependency, the lib module is configured to automatically update its flavor and build type to match.

[akien-mga]

Sounds great, thanks for the explanation :)