Add Thailand Translation

[dimaslanjaka]

Translated using standard language

PR Checklist

• The commit message follows guidelines for NexT.
• Tests for the changes was maked (for bug fixes / features).
  • Muse | Mist have been tested.
  • Pisces | Gemini have been tested.
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Code style update (formatting, local variables).
• Refactoring (no functional changes, no api changes).
• Documentation.
• Translation.
• Other... Please describe:

What is the current behavior?

Issue resolved: Add thailand translation

What is the new behavior?

• Add thailand translation

• Link to demo site with this changes: not yet tested

• Screenshots with this changes: not yet tested

How to use?

• create post

---
title: Post title
lang: th
---

Post body with thailand language

[welcome]

Thanks so much for opening your first PR here!

[CLAassistant]

All committers have signed the CLA.

[coveralls]

Pull Request Test Coverage Report for Build 3439988468

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 97.614%

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Totals
Change from base Build 3435438899:	0.0%
Covered Lines:	394
Relevant Lines:	399

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💛 - Coveralls

[stevenjoezhang]

We use Crowdin to manage translations: https://crowdin.com/project/hexo-theme-next You can register an account and log in to Crowdin

I have uploaded the translation to Crowdin: #586 Thanks!