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

[Thiago Milczarek Sayao]

> 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

-------------

Changes:
  - all: https://git.openjdk.org/jfx/pull/1009/files
  - new: https://git.openjdk.org/jfx/pull/1009/files/a50e2424..56b256cc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1009&range=02
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1009&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1009.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/1009/head:pull/1009

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