docs(scully): add spanish translation of the pre-requisites file and update getting started

[facurodriguez]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/scullyio/scully/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

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

Issue Number: #456

What is the new behavior?

• Adds the Spanish translation of the current version of the pre-requisites.md file.
• Updates Spanish getting started and adds a link to the Spanish pre-requisites page

Does this PR introduce a breaking change?

• Yes
• No

Other information

[Villanuevand]

LGTM!