xF2 Add-on User Mentions Improvements by Xon 2.10.2

• Fix "Template error: Macro email:sv_mention_macros:quote_subject is unknown"
• Add '[UMI] View mentionable user group members' permission
  • By default granted to registered and unregistered usergroups.
  • Controls if a user group member can see the member list for public user groups
  • Global option for how completely this is hidden, by default it returns no permission. But can completely hide the user group id (returning a 404), and not render the user group mention bbcode.

• Rework user mentioned/quoted email templates
  • Support sending quoted text when mentioned (or quoted)
  • Can be up to X characters, all characters or no characters.
• User mentioned/quoted emails now properly support email opt-out links
• User mentioned emails now support:
  • Reports
  • Profile Posts
  • Profile Post Comments
• Note; these content types are not suitable for large volumes of mentions generating emails due to this

• Remove options for unimplemented mini-avatar feature
• Workaround for when saving a user group, XF2 rebuilds all permission combinations when >8 combinations exist.
  • Only trigger a rebuild if changes are made, simply clicking save doesn't force a rebuild.
  • When using a background worker, only rebuild changed combinations not all permissions.

• Fix guest posting support