Do not create tables as InnoDB automatically, rely on connection default

As argued in #1675, this makes us slightly less reliant on MySQL.

src/Database/Migration.php

@@ -31,7 +31,6 @@ abstract class Migration
             'up' => function (Builder $schema) use ($name, $definition) {
                 $schema->create($name, function (Blueprint $table) use ($schema, $definition) {
                     $definition($table);
-                    $table->engine = 'InnoDB';
 
                     static::fixIndexNames($schema, $table);
                 });