This is a follow up of KAKFA-3421 to update the connect developer guide to include the configuration validation. Also includes a couple of minor fixes.
Author: Liquan Pei <liquanpei@gmail.com>
Reviewers: Jason Gustafson <jason@confluent.io>, Ewen Cheslack-Postava <ewen@confluent.io>
Closes#1366 from Ishiihara/connect-dev-doc