Move SPI\Persistence\Search to SPI\Search

Conflicts:
	eZ/Publish/Core/Persistence/Cache/LocationSearchHandler.php
	eZ/Publish/Core/Persistence/Legacy/Content/Search/Location/Handler.php
Deprecate SPI\Persistence\Handler search functions
Fix mising quoteColumn table name in Search gateway getQueryCondition
[UnitTest] Complete and enable 2 LocationSearchHandlerTest
Merge pull request #974 from ezsystems/move_spi_search

EZP-20463: Extract Search backend into own SPI