[ENHANCEMENT] An LLM Dashboard for latency, token usage, and cost

[hypernovas]

We are launching an LLM project, and I really love Phoenix given the tracing capability and clear UI. One thing we feel that would prevent us from adopting it is a aggregated stats tab as well as the alerts (e.g., connect to Slack) for each project (or multiple project). This is crucial for a production level LLM project.

Alternatively, it there could be a pointer to how I could implement such dashboard on my own would also be great. We are willing to contribute.

Something such as the following screenshots would be very helpful.