CI improvements: CodeClimate, Inch

[ffloyd]

Context

Right now CodeCov is used for the test coverage tracking.

On the other side, CodeClimate provides both maintainability and coverage tracking.

Inch-ci provides documentation coverage badge.

Task

• add Inch-CI badge to READMEs
• we want maintainability badge from CodeClimate, but CC also has test coverage tracking. To reduce the number of tools used in CI - switch to CC as a test coverage tracker.
• add CC badges for maintainability and coverage