Add some `.arclint` configuration options for `ArcanistJSHintLinter`.

Summary:
Allow `.jshintrc` and `.jshintignore` paths to be passed to `jshint`.

Ref T2039.

Test Plan: Added the `jshintrc` and `jshintignore` keys to an `.arclint` file that was configured to use `ArcanistJSHintLinter`. Ran `arc lint --trace` and inspected the flags that were passed to `jshint`.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: john.snow, epriestley, Korvin

Maniphest Tasks: T2039, T5085

Differential Revision: https://secure.phabricator.com/D9112