LPS-37409 Move BackgroundTaskStatusRegistryImpl to com.liferay.portal.backgroundtask in order to resolve portal startup error

Hi Julio,

Current trunk didn't startup this morning and after some investigation I stumbled upon this commit: https://github.com/juliocamarero/liferay-portal/commit/e993c800aab61c176de07cef995595b99595aedd.

Brian might have wanted to move BTSR* from "com.liferay.portal.backgroundtask.status" to "com.liferay.portal.backgroundtask", but BTSRI remained in its old place.

Thanks,
Laszlo