[ticket/12527] Remove translation editor from ACP
* nickvergessen/ticket/12527:
[ticket/12527] Fix "board’s language" vs "boards language"
[ticket/12527] Use a proper language string on confirm screen
[ticket/12527] Remove unnecessary language strings
[ticket/12527] Check whether the language exists
[ticket/12527] Restore missing files and variables check
[ticket/12527] Remove editor from template
[ticket/12527] Remove language file editor form ACP