Languages sync patch via command (docker issues #78)

[Victorivus]

Proposed Changes

• I added a command to core management sync_core_languages which fixes the error of languages having different IDs if we deleted some and made an exercise sync after (DETAIL: Key (language_id)=(4) is not present in table "core_language". docker#78)
• Temporal patch while Better handling of languages during exercise sync #1667 gets developped

Please check that the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Added yourself to AUTHORS.rst

Other questions

If you encounter the languages problem (e.g. wger-project/docker#78), just run:

• manage.py sync_core_languages
  or
• docker compose exec web python3 manage.py sync_core_languages

[Victorivus]

I didn't manage to get the test running locally if someone can help.

The command itself works as expected:

We delete language 22 (Croatian) and sync exercises, so it creates it with last id +1 (45 here)

The sync fails:

After running this new command sync_core_languages:
Croatian gets back to 22 and the sync is performed without problems

[Victorivus]

Tests weren't passing because it was Postgre specific. Now they do work (https://github.com/Victorivus/wger/pull/1/checks).

Changes made:

• Removed PostgreSQL-specific commands: Removed SET session_replication_role = 'replica'; and SET session_replication_role = 'origin';.
• Temporary table creation: Used CREATE TEMPORARY TABLE and handled the case if it's not supported by falling back to CREATE TEMP TABLE.
• Django ORM: Used Django ORM for updating or creating records in the core_language table.
• Database compatibility: Made sure the SQL used for inserting and updating records is compatible with both PostgreSQL and SQLite.

Test in "production" was done as so:

1. Run docker exec -ti wger_db psql -U wger
2. # DELETE FROM exercises_exercise WHERE language_id =22; DELETE from core_language where id=22;
3. The command sync-exercises (docker compose exec web python3 manage.py sync-exercises) will now throw errors and not work, it will create languages wth different ids than original ones.
4. Run this PR's command sync_core_languages (docker compose exec web python3 manage.py sync_core_languages)
5. Now sync-exercises (docker compose exec web python3 manage.py sync-exercises) will work properly as expected.

[Victorivus]

@rolandgeider just to let you know that I fixed the test pipeline if you want to rerun it

[rolandgeider]

haven't forgotten you, will take a look this weekend