Removed non-english markdown files with xliff versions (#17281)
Closes #17237
Summary of the issue:
As translated markdown files are generated from xliff files for languages that have been moved to Crowdin, markdown files for these languages should not be under version control.
Description of user facing changes:
None.
Description of development approach:
Removed files listed in #17237.
Testing strategy:
Built locally and on AppVeyor.
Known issues with pull request:
This will need to be done as further languages are moved over from l10n to Crowdin.
