added optional SQL-prepared statements usage

[IVDeg]

On our project, we encountered memory leaks when using SQL-prepared statements. Therefore, it was decided to add the ability to disable this functionality

[mhthnz]

Hey! Thank you for your pr. Can you provide more information? Because may be we will find another way to patch that code.
Tell me please:

1. Is memory leaks on php side or on database side (like this Segmentation fault while using prepared statements without closing them tarantool/tarantool#6422)
2. What part of project it was? (cron task/console command/php-fpm handler)
3. Can you provide reproducible script where memory leak is?