tools: rename eslintrc to an undeprecated format

As per ESLint documentation,
http://eslint.org/docs/user-guide/configuring#configuration-file-formats
the file format .eslintrc is deprecated. This patch just renames the
files to .yaml and the structure is already in yaml format.

PR-URL: nodejs#7699

Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Michaël Zasso <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Prince John Wesley <[email protected]>
Reviewed-By: Johan Bergström <[email protected]>
Reviewed-By: Rich Trott <[email protected]>

Author: thefourtheye