feat: generate avatars for display name with chinese characters

[kesselb]

• Resolves: https://help.nextcloud.com/t/the-problem-of-automatically-generating-an-avatar-for-a-chinese-user-name/177750

Summary

We are using NotoSans-Regular for generating avatars.

If the character is not supported by NotoSans-Regular the users end up with an avatar like below:

The pull request here adds another font and uses a poor regex to flip out the font when chinese characters are detected. The font actually should cover even more characters.

@danxuliu did a deep dive into the topic a while ago and wrote down everything you need to know: #25529

TODO

• Testing Testing
• Do we want to ship another font
• Extend regex to match supported characters for NotoSC font

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)

[AndyScherzinger]

@kesselb can you tell a bit about the state of the PR? 😊

[kesselb]

@AndyScherzinger Added some context to the pull request.

I never got feedback in the forums if the suggested patch works, and therefore did not continue.

This font topic is a rather complicated one, and I have no idea if that's a sane approach.