feat: fetch remote i18n (partial - for channels only)

[marrouchi]

Motivation

The following PR:

• Add a hook to load i18n translations from the API (channels settings)
• Enforce typing in channel and establish type safeguards
• Enhances Settings typing
• Establish distinction in naming of extension vs group (hyphen vs underscore)

How to test

AC :

• Settings should show the channels settings : Web channel and Livechat tester
• The live chat tester should work as expected in the visual editor
• The widget should continue to work as well (both in container and as a wordpress plugin for example)

Related PR:

Hexastack/hexabot-channel-messenger#2

Type of change:

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added unit tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[yassinedorbozgithub]

• Settings ✅
  

• Visual editor ✅
  

• WordPress ✅
  

LGTM 🚀