Remove unused language choices

Problem

There are several languages currently available in GitLab as a user preference, but their translation levels are between 0% and 2%. This kind of a "false" choice creates a disappointing experience for the user, as there is pretty much no change in the UI once it is selected.

Solution

We will remove these choices from the UI until they reach at least 10% translated strings.

TODO

• !38312 (merged)
  • Make the list of languages not available in the UI
  • Update the documentation with the information that languages with less than 2% of translations won't be available in the UI.

The List

These languages have 2% translation levels or less and are currently available in the UI (the numbers in the parenthesis are the current number of users with this selection and that number represented as a % of the total number of users):

• Filipino (2 - 0.00%)
• Polish (1,435 - 0.03%)
• Dutch (472 - 0.01%)
• Indonesian (930 - 0.02%)
• Czech (378 - 0.01%)
• Bulgarian (37 - 0.00%)
• Esperanto (25 - 0.00%)
• Galician (27 - 0.00%)