French UI for IMAGE

[notkaramel]

PR Description

• This PR is an expansion of #327 and a continuation of #328

  Major changes

• Refactored hard-coded UI elements of IMAGE to support multiple languages via _locales/[language]/messages.json. Here I focus on English and French.
• Refactored inconsistent and redundant codes within the browser extension
• Adjusted some CSS styling to fit localisation. (selector ids, classname)
• Pages changed:
  • info
  • errors
  • feedback
  • firstLaunch
  • options
  • progressBar
  • launchpad
• Other changes:
  • Option page alerts/ elements created on the spot
  • maps embedded button
  • highCharts embedded button

[notkaramel]

From sprint meeting July 04, 2023, we've decided that the audio cues for "IMAGE request sent" and such will be its own work item, with more research/prototypes and discussion to be made and will be presented in our UX meeting. This PR focuses on the interface of the extension, keeping the old English TTS audio cues.