Development: Add CI action to check that German and English translation keys are consistent

[b-fein]

Checklist

General

• I tested all changes and their related features with all corresponding user types on a test server.
• This is a small issue that I tested locally and was confirmed by another developer on a test server.
• Language: I followed the guidelines for inclusive, diversity-sensitive, and appreciative language.
• I chose a title conforming to the naming conventions for pull requests.

CI script

• I strictly followed the server coding and design guidelines.
• I documented the code.

Motivation and Context

As noted in #9369, there are discrepancies between the translation keys in German and English. We want to avoid this.

Description

This PR adds a helper script that runs in a CI action and checks that the translation keys defined in German and English are consistent. In detail it checks that

• the de/ and en/ directories contain files with the same names,
• all of such pairs of equally named files contain the same keys, and
• there are no duplicate keys defined.

The script accepts either two directories to compare the full directory content, or two files to compare the content of two files.

Steps for Testing

You can run the script locally. It should report the missing files as noticed in #9369 and find set of translation keys that only exist in German/English.

The CI action itself will maybe not run on this branch since configuration files are taken from the default branch (?), and we do not yet make changes to the translation files here.

Review Progress

Code Review

• Code Review 1
• Code Review 2

Manual Tests

• Test 1
• Test 2

Test Coverage

n/a

@coderabbitai ignore

[krusche]

Great additional check, thank you 👍

[raffifasaro]

code LGTM

[magaupp]

Tested locally. The flattened keys in the output are always prepended with an additional dot:

Missing English translation keys:
.artemisApp.attachmentUnit.createAttachmentUnits.split.empty
.artemisApp.courseCompetency.create.averageMastery
.artemisApp.courseOverview.exerciseFilter.resetFilter
...

[b-fein]

The additional dot at the start is intentional since it represents a JSON pointer that way that can be directly used with jq.