Add lint task for translations

[alexander-schranz]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Fixed tickets	fixes #issuenum
Related issues/PRs	https://github.com/sulu/sulu/pull/7578, https://github.com/sulu/sulu/pull/7577
License	MIT
Documentation PR	sulu/sulu-docs#prnum

What's in this PR?

Add lint task for translations.

Why?

Add a lint task to show which translation where missed when run composer lint.

bin/console debug:translation en --only-missing

Todo

• [x] https://github.com/sulu/sulu/pull/7578