feat: use OpenAlex for all unsupported DOI registry agents

[ewan-escience]

Use OpenAlex for unsupported DOI RAs

Changes proposed in this pull request

• On the frontend, when searching for a DOI that is not from Crossref or DataCite, use OpenAlex instead
• Same when bulk importing on the frontend
• Same for the mentions scraper

How to test

• docker compose down --volumes && docker compose build --parallel && docker compose up --scale data-generation=0
• Now that there are no mentions, create a software or project page, search for 10.3968/10006, it should be found using OpenAlex, but don't add it
• Do a bulk import of mentions (use e.g. Mention feedback #808) including this DOI, it should be found, import them
• Run the mentions scraper (a few times if necessary):
• docker compose exec scrapers java -cp /usr/myjava/scrapers.jar nl.esciencecenter.rsd.scraper.doi.MainMentions
• The scraped_at field at http://localhost/api/v1/mention should be set, no errors should be generated
• Do some more testing with other DOIs (use e.g. Mention feedback #808) to see if everything still works

Closes #1321

PR Checklist:

• Increase version numbers in docker-compose.yml
• Link to a GitHub issue
• Update documentation
• Tests

[sonarcloud]

Quality Gate passed for 'scrapers'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[sonarcloud]

Quality Gate passed for 'rsd-frontend'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[jmaassen]

Nice work!

It also seems to work for DOIs minted by the EU, such as 10.2777/28598