Slovak translation

[p3lo]

Description

This is the initial version of the Slovak translation, which can also be useful for Czechs because our nations have very similar languages. I do not have the ability to launch this project and test it. I only did the translation. Please test to see if everything is alright. Thank you for this great project.

Checklist:

• [ x ] I have read the Contribution Guidelines
• [ x ] I have performed a self-review of my own code
• [ x ] I have commented my code, particularly in hard-to-understand areas
• [ ? ] My changes generate no new warnings

Contributor License Agreement

By submitting this pull request, I acknowledge and agree that my contributions will be included in Stirling-PDF and that they can be relicensed in the future under the MPL 2.0 (Mozilla Public License Version 2.0) license.

(This does not change the general open-source nature of Stirling-PDF, simply moving from one license to another license)

[Frooodle]

Please add entry in readme as well for new language in same format !

[p3lo]

I have updated readme file as well. thank you