Translate README to Spanish

### Title
Translate README to Spanish

### Description
**Is your feature request related to a problem? Please describe.**
The current README file for EasyMDE is only available in English. This limits accessibility for Spanish-speaking users who may find it challenging to understand the documentation and usage instructions.

**Describe the solution you'd like**
Translate the entire README file into Spanish and add a link at the top of the README for users to switch to the Spanish version. This will make EasyMDE more accessible and user-friendly for Spanish-speaking users.

**Describe alternatives you've considered**
An alternative solution would be to create a separate repository for translations, but this may lead to confusion and maintenance challenges.

This enhancement will help broaden the user base and improve usability for non-English speakers.

**Additional context**
Here is a mock-up of how the README could include a language switcher at the top:

```markdown
# EasyMDE - Markdown Editor

[](README.md) [](README.es.md)

Start by reading the existing README and review the proposed README.es.md language-switcher link. Translate the entire README into Spanish, add the English and Spanish links at the top, and verify that both files and links render correctly.

Written by the indexing model from the issue text.