RFR: JDK-8223373: Remove IntelliJ IDEA specific files from the source code repository

[Kevin Rushforth]

On Mon, 23 Jan 2023 23:55:51 GMT, Thiago Milczarek Sayao <tsayao at openjdk.org> wrote:

> This PR does:
> 
> - Remove specific Idea files and let it be imported from gradle;
> - Adds checkstyle (to use with checkstyle plugin - it will let you know style mistakes);
> - Configures auto-format to sun style (with the changes mentioned in [Code Style Rules](https://wiki.openjdk.org/display/OpenJFX/Code+Style+Rules));
> - Automatically sets Copyright notice (updates year too);
> - Run configurations for samples/toys and builds.

This touches `build.gradle` and `settings.gradle` in addition to IDE-specific files. Those changes will need additional review, so I'm requesting two reviewers.

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PR: https://git.openjdk.org/jfx/pull/1009