Implement getLanguages query

[jennchenn]

Notion ticket link

Implement getLanguages query

Implementation description

• added query to get languages

Steps to test

1. Rebuild containers and make sure database is up to date
2. Run this query
3. Verify response looks like:

{
  "data": {
    "languages": [
      "ARABIC",
      "ASANTE TWI",
      "ASSAMESE",
      "BENGALI",
      "BHILI",
      "CATALAN",
      "CHATINO",
      "DANISH",
      "DUTCH",
      "ENGLISH_UK",
      "ENGLISH_US",
      "ENGLISH_INDIAN",
      "ESPERANTO",
      "FRENCH",
      "GEORGIAN",
      "GERMAN",
      "GREEK",
      "GUJARATI",
      "HEBREW",
      "HINDI",
      "INDONESIAN",
      "ITALIAN",
      "JAPANESE",
      "KANNADA",
      "KAZAKH",
      "KHMER",
      "KOTAVA",
      "KURDISH",
      "KUTCHI",
      "LIDEPLA",
      "MALAYALAM",
      "MALTESE",
      "MANDARIN",
      "MARATHI",
      "NEPALI",
      "NORWEGIAN",
      "ORIYA",
      "POLISH",
      "PORTUGUESE",
      "PUNJABI",
      "ROMANIAN",
      "RUSSIAN",
      "SANSKRIT",
      "SANTALI",
      "SPANISH",
      "SWAHILI",
      "TAMANG",
      "TAMIL",
      "TELUGU",
      "TURKISH",
      "UKRAINIAN",
      "URDU"
    ]
  }
}

What should reviewers focus on?

• does the query work as expected?

Checklist

• My PR name is descriptive and in imperative tense
• My commit messages are descriptive and in imperative tense. My commits are atomic and trivial commits are squashed or fixup'd into non-trivial commits
• For backend changes, I have run the appropriate linters: docker exec -it planet-read_py-backend_1 /bin/bash -c "black . && isort --profile black ." and I have generated new migrations: flask db migrate -m "<your message>"
• I have requested a review from the PL, as well as other devs who have background knowledge on this PR or who will be building on top of this PR

[gaoxk]

niceeeee 😎