ZF-11884: Slovak translation of Zend_Validate messages

Description

Add Slovak translation of Zend_Validate error messages.

Comments

File has been added in ZF2 GitHub pull request #608

There are still problems which should be fixed

File that has been previously attached to this bug is for next minor release of ZF1. Newly translated file for ZF2 has been updated in pull request #608 on GitHub.