Testing: Add test coverage and CI badges to Readmes

[dcwalk]

Building on #37, each readme README.md should also have:

1. [x] Repo Badges for: Test Coverage, Continuous Integration

Notes:

• We use Shields.io for badges
• We use CircleCI for CI
• We don't have a code coverage service, options for golang include: codecov or ?? gocover

Therefore, adding the following two lines to a README should do the trick:

[![CI](https://img.shields.io/circleci/project/github/datatogether/REPONAME.svg)](https://circleci.com/gh/datatogether/REPONAME) [![Coverage](https://img.shields.io/codecov/c/github/datatogether/REPONAME.svg)](https://codecov.io/gh/datatogether/REPONAME)

Here's what they look like rendered:

relevant repositories are:

• [x] api
• [x] content
• [x] coverage
• [x] identity
• [x] patchbay
• [x] task_mgmt

[dcwalk]

Here is an example of badges for other services:

[![GitHub](https://img.shields.io/badge/project-Data_Together-487b57.svg?style=flat-square)](http://github.com/datatogether)
+[![Slack](https://img.shields.io/badge/slack-Archivers-b44e88.svg?style=flat-square)](https://archivers-slack.herokuapp.com/)
+[![License](https://img.shields.io/github/license/mashape/apistatus.svg)](./LICENSE) 

[dcwalk]

An example for Data Together: https://img.shields.io/circleci/project/github/datatogether/webapp.svg

[b5]

DONE DONE AND DONE