Let creating property delegate use create() instead of register()

[bamboo]

To minimize confusion when migrating away from the eager API.

[JLLeitschuh]

The config avoidance API is what the new API Gradle wants users to be using moving forward.
These changes seem to be at odds with that goal. I'm confused.

[eskatos]

@JLLeitschuh use registering or existing for configuration avoidance. creating and getting should be eager, they should simply delegate to create() and getByName(), just like registering and existing respectively delegate to register() and named(). This change and #1247 makes the eager delegated properties behavior more coherent, less surprising.

[JLLeitschuh]

Okay, this makes sense. I'm glad that there's an alternative that still provides support for config avoidance.