FIX #42 - Downscaling Loki wipes its configuration (#44)

* FIX #42 - Downscaling Loki units does not produce a bad config file

* Fix and add one more unit test

* Update prometheus_remote_write lib

* Update loki_push_api lib

* Following prometheus-remote-write changes

* Making test simpler and easy to maintain

* Tests simplified, added mocks removed

* Update loki lib

* Update Loki Lib

* Fix _loki_config()

* Remove warning

* Improve unit tests

* Catch APIError exception

* Linting