Remove the getConfig and setConfig method.

Summary: It seems that there is a lot of overlap between getConfig / setConfig and getLinterConfigurationOptions / setLinterConfigurationValue respectively.

Test Plan: arc lint and arc unit.

Reviewers: epriestley, Blessed Reviewers

Subscribers: epriestley, Korvin

Differential Revision: https://secure.phabricator.com/D9067