Refactor and document configuration settings

Description

a) Move config.js settings into config.json
b) Auto-generate config.js from config.json
c) Deprecate unused config settings
d) Refactor config settings where appropriate
e) Document config settings // draft of config settings available at: http://forum.mattermost.org/t/documenting-config-json-settings/162 (list updated as we get in community questions)

QA Test Steps

None

Mana

None

Assignee

Corey Hulen

QA Assignee

None

Reporter

Ian Tien

Epic Link

Fix versions

None

Mattermost Team

None

Sprint

None

Labels

QA Testing Areas

None

GitHub Issue

None

Components

None
Configure