Enable web-based translation editor

[henrygab]

JSON now supports detecting when a translated string is (may be) out-of-date.
Here's a few things the editor should do:

• Load all languages
  • Using tabbed UI, one language per tab
• Enable word-wrap for localized and en-us columns
• Detect when any row's value was changed for a translation
• add filters to each datagrid
  • Filter by "old" checkbox
  • Filter by ID
• Load the translations from github main branch (rather than relative to page)
• Automatically update list of known translations
  • Maybe query what language templates are available on github?
• SAVE THE CURRENT TRANSLATION DATA TO OUTPUT TAB (w/a copy to clipboard button?)
  • User can copy/paste into a file, but they need to know git...
  • Some other way to submit?
  • Is there a way in Javascript to have insertion order == enumeration order?
• Button to create a new translation (all empty, but based on current en_us)
• Button on each row to remove that row
• At bottom, empty new row for adding a new row
  • use autocomplete for the ID
  • automatically fill in existing EN_US data
  • exclude any existing rows' ID from autocomplete
• Mark rows with errors:
  • ID no longer exists in en-us
  • Different format specifiers (at load time)
    • Auto-clear that format specifier error on any edit
    • Better ... implement format specifier extraction in web also, to flag immediately non-matching
  • For outdated rows, show the old en_us value as a tooltip?