RFR: 8311227: Add .editorconfig so IDEs would pick up the common settings automatically: indent, trim trailing whitespace [v3]

[David Linus Briemann]

> Add an .editorconfig to define indentation, trim trailing whitespace and open curly brace position for C++ and Java.
> This allows various editors to easily infer basics of the coding style.

David Linus Briemann has updated the pull request incrementally with one additional commit since the last revision:

  make editorconfig hotspot specific

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Changes:
  - all: https://git.openjdk.org/jdk/pull/23693/files
  - new: https://git.openjdk.org/jdk/pull/23693/files/349997a8..c0e5ed47

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23693&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23693&range=01-02

  Stats: 11 lines in 2 files changed: 3 ins; 8 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/23693.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23693/head:pull/23693

PR: https://git.openjdk.org/jdk/pull/23693