Support alerting a percentage of allocation on tag values over time period

### Problem Statement

I have a use case where I need to create an alert based on a tag set when one or more values in that tag set reach a certain percentage threshold. For example, I have a collection of issues with a custom tag where the issue values of that tag are under normal circumstances are evenly distributed across all tags. I would like to trigger an alert when one or more of those tags approaches a certain percentage across the issue collection over the time period I have selected. This will help me identify potential hotspots as they relate to the tags I am monitoring.

### Solution Brainstorm

Add support for creating alerts around tag percentages over time, or add support in the query syntax that would allow me to aggregate across all tags any tag over a certain percentage threshold.

### Product Area

Alerts