RFR: JDK-8223373: Remove IntelliJ IDEA specific files from the source code repository [v3]

[Marius Hanl]

On Thu, 23 Feb 2023 00:41:28 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.
>
> Thiago Milczarek Sayao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Use java 17 by default

Looks good to me. Tested with the latest IntelliJ version, everything works as expected.
The addition to the `.gitignore` is also very helpful and I can confirm I get no unrelated IntelliJ/Sonarlint files anymore.
Gradle changes also looks fine as far as I can tell. But someone else should probably have a look as well.

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Marked as reviewed by mhanl (Committer).

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