EZP-21516: added CONTAINS operator
EZP-21516: implemented Criterion field value conversion
EZP-21516: configure Legacy Handler with Criterion value conversion
EZP-21516: handle CONTAINS operator in Solr storage
EZP-21516: added SearchField for Country field type
EZP-21516: updated Legacy SearchHandler tests
EZP-21516: updated SearchService integration tests
CS: removed extra new line
PHPDoc: fixed class description
EZP-21516: added has() method to Converter field value handler  registry
Merge pull request #507 from ezsystems/fix-EZP-21516-search-field-ezselection-multiple

Fix EZP-21516: Field criterion: unable to query ezselection using Multiple Choice