Add byContains and byJsonPath throughout

- Change to JSON Path function to work around PDO syntax quirk

tests/unit/Query/ExistsTest.php

@@ -60,7 +60,7 @@ class ExistsTest extends TestCase
     public function testByJsonPathSucceedsForPostgreSQL(): void
     {
         Configuration::$mode = Mode::PgSQL;
-        $this->assertEquals('SELECT EXISTS (SELECT 1 FROM lint WHERE data @? :path::jsonpath)',
+        $this->assertEquals('SELECT EXISTS (SELECT 1 FROM lint WHERE jsonb_path_exists(data, :path::jsonpath))',
             Exists::byJsonPath('lint'), 'Existence query not generated correctly');
     }