Automatically add metadata to Hugging Face Hub repos when uploading projects

[juhoinkinen]

With this PR, when running annif upload:

• if README.md (Model Card) does not exist in the destination repository, then README.md is created with default contents and some metadata of the uploaded projects,
• if README.md exists, its metadata are updated as necessary.

Closes #790.

The metadata includes these:

language:
- <language-code tags automatically obtained from the uploaded projects>
tags:
- annif   # custom tag
pipeline_tag: text-classification  # HFH tag

The Model Card text content is very minimal; it has just the repo name as the heading and info about how to download projects from the repo, see an example in https://huggingface.co/juhoinkinen/Annif-models-upload-testing.

[juhoinkinen]

About @osma's suggestions in https://github.com/NatLibFi/Annif/issues/790#issuecomment-2137376118:

For example it could include the Annif version used for training, the backend, vocabulary name and size, possibly some of the hyperparameters / configuration settings as well.

• Annif version:
  • The Annif version used for training is not stored anywhere at the moment; the version performing the upload is not necessarily the same. This kind of metadata should be first stored somewhere, for which there is the issue https://github.com/NatLibFi/Annif/issues/329
• Backend, vocabulary name and other project configuration:
  • These are available in the <project-id>.cfg files, accessible from the Files and versions tab, e.g. https://huggingface.co/NatLibFi/FintoAI-data-YSO/blob/main/yso-en.cfg, so I think they are not worth putting to the Model Card.

[sonarcloud[bot]]

Quality Gate passed

Issues
6 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 99.65%. Comparing base (3b5f7a1) to head (125565e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #793 +/- ## ======================================= Coverage 99.64% 99.65% ======================================= Files 91 91 Lines 6817 6886 +69 ======================================= + Hits 6793 6862 +69 Misses 24 24 ```

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[juhoinkinen]

@CodiumAI-Agent /review

[CodiumAI-Agent]

PR Reviewer Guide 🔍

⏱️ Estimated effort to review [1-5]	3
🧪 Relevant tests	Yes
🔒 Security concerns	No
⚡ Key issues to review	Possible Bug: Ensure that the upsert_modelcard function handles cases where project language data might be missing or malformed. The current implementation assumes that proj.vocab_lang is always available and valid.
	Data Integrity: The merging of languages in upsert_modelcard should handle duplicates and potential case sensitivity issues to avoid incorrect language tags in the Model Card.

[juhoinkinen]

Possible Bug: Ensure that the upsert_modelcard function handles cases where project language data might be missing or malformed. > The current implementation assumes that proj.vocab_lang is always available and valid.

Good point by the AI, but I think the project language is always set if this point is reached...?