RFR: 8311227: Add .editorconfig so IDEs would pick up the common settings automatically: indent, trim trailing whitespace [v2]

[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:

  simplify editorconfig

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Changes:
  - all: https://git.openjdk.org/jdk/pull/23693/files
  - new: https://git.openjdk.org/jdk/pull/23693/files/02f923e2..349997a8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=23693&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=23693&range=00-01

  Stats: 6 lines in 1 file changed: 0 ins; 5 del; 1 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