Implement EZP-22564: LocationSearch powered by Solr search

This is a combination of 32 commits:
EZP-22564: fixed docblock missing return hint

EZP-22564: schema: added fields necessary for block documents

EZP-22564: adapt gateway for block documents

EZP-22564: adapt handler for indexing Locations

EZP-22564: adapt criterion visitors for block documents

EZP-22564: implement and configure aggregate visitors for Location search

EZP-22564: implement Location search handler and gateway

EZP-22564: configure Location search for legacy_solr

EZP-22564: implement and configure criterion visitors

EZP-22564: implement and configure sort clause visitors

EZP-22564: temp: disable skipping Location search tests

EZP-22564: add missing test fixtures

EZP-22564: remove redundant fields from Content documents

EZP-22564: add SPI Document

EZP-22564: add regression suite to legacy_solr tests

EZP-22564: use SPI Document

EZP-22564: denormalize: Content name in main language

EZP-22564: implement ContentName sort clause

EZP-22564: denormalize: Section name and identifier

EZP-22564: implement SectionName and SectionIdentifier sort clauses

EZP-22564: denormalize: modification and publication dates

EZP-22564: implement DatePublished sort clause

EZP-22564: implement DateModified sort clause

EZP-22564: fixed: wrong class configured

EZP-22564: fixed: field name conflicts when using parent filter

EZP-22564: fixed condition

EZP-22564: add Content id to Trash signal

EZP-22564: implement CreateLocation Solr slot

EZP-22564: added second param Content id to deleteLocation()

EZP-22564: adapt gatway for indexing document blocks

EZP-22564: adapt handler for indexing document blocks

EZP-22564: Fix misc rebase issues