I18n Sync Down & Out

This PR contains all changes to translations made since the last sync (usually a week).

To Review:

Look through the changes in each of the commits and verify that all changes are expected. Note that it is not necessary to review every single "dashboard i18n update" commit. These commits are batched by language to make it easier to review just a couple commits in this category.

Things to Note:

• We expect translation changes to come in on a regular basis; new strings will be translated, existing translations will be updated, and source string removals will result in translations for those strings also being removed.

• We expect translations to arrive in large batches, so don't worry if you see a large group of changes in a specific language.

• We do not usually expect to see a large number of formatting changes, or batches of changes that apply to strings in every single language. If you see this, it usually means either that a code change went in or that something broke.

Known Issues:

• If the CI unit tests fail at the grunt messages:all step, they will typically fail with a message like:

  [2019-10-04 02:38:57] Running "messages:all" (messages) task
  [2019-10-04 02:39:00] Warning: Error processing localization file i18n/common/zh_tw.json: SyntaxError: Expected [0-9a-zA-Z$_] but "\u8A0A" found. Use --force to continue. 
  

  This usually means that a translator has translated one of the MessageFormat variables. In this case, you should find and fix the offending translation in crowdin, and then manually update the associated strings in i18n/locales and apps/i18n.

  See ab3e5d1 and 0fca376 for an example.

To Deploy:

Once one or two people have reviewed and approved this change and the tests are passing, ship it!

It's not necessary to wait for everyone on the team to review.