* Add support for streaming (push) history
Currently we poll for history data, like logbook we can stream
this data to avoid database overhead
* Update homeassistant/components/history/__init__.py
* merge filter
* expose new api
* expose new api
* expose new api
* expose new api
* coverage
* tests
* fixes
* tweak
* tweak
* tweak
* DRY
* leaky
* test for specific entities
* test for specific entities
* test for specific entities
* test for specific entities
* test for specific entities
* cover
* cover
* more cover
* tweak
* make sure it works before history starts
* fix test
* cover
* tweak
* make sure we unsub on overflow
* Update homeassistant/components/history/__init__.py
* Update homeassistant/components/history/__init__.py
* fix race in test
* fix db executor access
* relo above task creation