Consolidate frontend (#9915)

* Consolidate frontend

* Remove home-assistant-polymer submodule

* Convert to using a pypi package for frontend

* fix release script

* Lint

* Remove unused file

* Remove frontend related scripts

* Move hass_frontend to frontend REQUIREMENTS

* Fix tests

* lint

* Address comments

* Lint + fix tests in py34

* Fix py34 tests again

* fix typo