Add support for user display name_styles

[TheServerit]

Summary

This PR adds display_name_styles property to user.
As a part of it, it also introduces 2 new enums for the font type and effect type.

Note: I do not know whether this should be included in on_user_update.

Checklist

• If code changes were made then they have been tested.
  • I have updated the documentation to reflect the changes.
• This PR fixes an issue.
• This PR adds something new (e.g. new method or parameters).
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)

[Soheab]

Duplicate of #10285