Replace 'pre-commit-hook' lib with 'pre-commit'

[gblejman]

Summary

• 'pre-commit-hook' creates unnecessary .jshintignore and .jshintrc files when installing, which we don't need since we are using eslint
• 'pre-commit' just installs the hook

Then we can also get rid of this line in package.json:

"init": "rimraf .validate.json && rimraf .jshintrc",

reference: https://www.npmjs.com/package/pre-commit

working on the PR @ericelliott