fix some translated strings and add Grunt toolchain for translation files

[benlk]

Changes

This pull request makes the following changes:

• adds text domains for a couple of __( calls
• adds Largo's latest trunk: WPBuddy/largo@INN:v0.7-prerelease1...5901819
  • changes an ID #header-social to a class name header-social in Moved id to class in HTML, changed CSS to match WPBuddy/largo#1826 — doesn't affect any Caribbean styles
  • XAMPP fixes: Remove filesystem paths from the filepaths that we run validate_file() on WPBuddy/largo#1850
  • the most-recent round of translatability fixes: Translatability fixes WPBuddy/largo#1858

Why

For #96

Testing/Questions

Features that this PR affects:

• labels on a couple blocks
• grunt
• things that were already tested in Largo

Questions that need to be answered before merging:

• Is this PR targeting the correct branch in this repository?
• what other testing is needed?

Steps to test the grunt toolkits:

1. npm i
2. grunt

Steps to test the translation stuff:

1. Install https://wordpress.org/plugins/theme-check/ and run it against the caribbean theme
2. The Theme Check results should not come back with any errors regarding translation.

[benlk]

This has been updated to the latest Largo.

[benlk]

This is deployed to staging.