Alert Improvements by Xon 2.13.0

• Require StandardLib v1.22.0+
• Fix bulk alert 'mark read' would fail if there was no unread alerts on the current page but the user had unread alerts
• Fix changing Unread alert icon/Recent alert icon did not trigger XF2.3 font-awesome icons to be consistently added
• Rework how alert read status icon is added to an alert
  • Add Just read alert icon style properties to style a just read alert icon and give it a tooltip phrase.
    • This icon is disabled by default for new installs. Upgrades will inherit Unread alert icon flag to enable this functionality per-style
  • Update various alert icons to match between XF2.2 and XF2.3, and rename icon style property names to be less confusing
    • "Unread" alert icon is now fas fa-star (solid star)
    • "Just toggled read" alert icon is now fas fa-star-exclamation (solid star with an exclamation in the middle)
    • "Recent read alert" icon is now far fa-star (hollow star)

• Fix edge case where clicking 'mark read' on an alert or the 'all' alerts button would miss updating alerts
• Add confirmation prompt when clicking "mark read" for marking alerts as read.
• Add per-user "Prompt on bulk mark read" option. Controlled by the global "Mark-read prompt opt-out" option.

Require StandardLib v1.21.0+
XF2.3 support
Recommend a minimum of XF2.3.2, as otherwise alert totals do not update as expected

Add "Use stock UI for marking alerts as read" style property (default disabled)

• When the user's alert count is non-zero, the alert-popup is forced to fetch unread alerts first, and if no unread alerts are discovered this indicates the user's alert count is out-of-sync and needs to be reset.

• Add explain text to the "Use custom" value for "Alerting Preferences" per-user option
• Add "[Alert Improvements] Can customize advanced alert preferences" permission to control is a user can change the following per-user preferences: "Alerts page options"/"Alert pop-up options"/"Alerts summarize threshold"
  Permission granted to Registered user group by default

• Fix incorrect phrase for default alert type in admincp
• Fix new alert types could be opted out by default instead of opt-in
• Fix user's alert preferences may not save with some configurations
• On alert opt-out list; only render "reset" checkbox for non-default values

• Fix setting "Alerts page skips summarizing" in "User Registration" to false wasn't applied to new accounts

• Fixes for grouped/summarized alerts
• Group by newest alert not oldest when computing alert summary data
• When gluing together per-content type reaction summary, use ", " not just whitespace.

• Fix unsetting "Pop-up auto-read" for some XF stock alerts would fail