Language selector

• new item in top level nav bar
  • icon for languages: Material Icons Translate
  • currently selected language
  • popup menu with available languages
  • clickable link for each language that allows copy via context menu by browser
• popup on page load if different language settings found
• language data in TT stash from Controller::Root
• new column language in users table or new table like user_settings

Language codes without country code because we’ll have only 2 languages at first and no physical relations like shipping related to countries. Language codes follow two letter ISO 639-1:

• en
• de

Language selection logic:

• priority of selection sources:
  1. URL query parameter language
  2. account
  3. session
  4. browser
  5. default: en
• switching languages writes to 3) session and if user is logged in also to 2) account
• the URL query parameter is not passed via links on the rendered HTML page
• if settings 1) URL, 2) account and 3) do not equal, popup is shown
• GeoIP will currently not be implemented