Piglow support (#5302)

* Add support for Piglow

* Updated coverage and requirements

* Add support for Piglow

* Updated coverage and requirements

* Fix linting errors

* Fix linting errors

* Remove trailing whitespace

* Shorter lines

* Remove trailing whitespace

* Update piglow.py

* Pinned piglow version

* Remove unused method

* Remove unused imports

* Fix lint errors

* Update requirements all

* Updated Piglow to allow the component name to be changed

* Fix imports

* Pass in name

* The piglow platform now fails if it cannot detect the piglow device

* Tidy subprocess import