Improve community prefix search

[carlinmack]

:heart: Thank you for your contribution!

Close https://github.com/inveniosoftware/invenio-app-rdm/issues/2759

Description

Please describe briefly your pull request.

• add edge_ngram prefix search for community titles
• add test case to verify (which fails without changes to mapping)

Checklist

Ticks in all boxes and 🟢 on all GitHub actions status checks are required to merge:

• [x] I'm aware of the code of conduct.
• [x] I've created logical separate commits and followed the commit message format.
• [x] I've added relevant test cases.
• [x] I've added relevant documentation.
• [ ] I've marked translation strings.
• [x] I've identified the copyright holder(s) and updated copyright headers for touched files (>15 lines contributions).
• [x] I've NOT included third-party code (copy/pasted source code or new dependencies).
  • If you have added third-party code (copy/pasted or new dependencies), please reach out to an architect.

Frontend

• [ ] I've followed the CSS/JS and React guidelines.
• [ ] I've followed the web accessibility guidelines.
• [ ] I've followed the user interface guidelines.

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1. You license your contribution under the same terms as the current repository’s license.
2. You agree that you have the right to license your contribution under the current repository’s license.

[carlinmack]

rebased on master