Revert fulltext detection in driver

lib/Db/Driver.php

@@ -76,7 +76,4 @@ interface Driver {
      * - "like": the case-insensitive LIKE operator
      */
     public function sqlToken(string $token): string;
-
-    /** Indicates whether the implementation is capable of full-text searching */
-    public function fulltextEnabled(): bool;
 }

lib/Db/MySQL/Driver.php

@@ -212,8 +212,4 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
     public function prepareArray(string $query, array $paramTypes): \JKingWeb\Arsse\Db\Statement {
         return new Statement($this->db, $query, $paramTypes, $this->packetSize);
     }
-
-    public function fulltextEnabled(): bool {
-        return false;
-    }
 }

lib/Db/PostgreSQL/Driver.php

@@ -221,8 +221,4 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
     public function prepareArray(string $query, array $paramTypes): \JKingWeb\Arsse\Db\Statement {
         return new Statement($this->db, $query, $paramTypes);
     }
-
-    public function fulltextEnabled(): bool {
-        return false;
-    }
 }

lib/Db/SQLite3/Driver.php

@@ -179,8 +179,4 @@ class Driver extends \JKingWeb\Arsse\Db\AbstractDriver {
         $this->exec((!$rollback) ? "COMMIT" : "ROLLBACK");
         return true;
     }
-
-    public function fulltextEnabled(): bool {
-        return false;
-    }
 }