Add config flow for OpenUV (#16159)

* OpenUV config flow in place

* Test folder in place

* Owner-requested comments

* Tests

* More tests

* Owner-requested changes (part 1 of 2)

* Updated requirements

* Owner-requested changes (2 of 2)

* Removed unnecessary import

* Bumping Travis

* Updated requirements

* More requirements

* Updated tests

* Owner-requested changes

* Hound

* Updated docstring