Expose more metrics, comparable to redis-exporter

**Did you search GitHub Issues and GitHub Discussions First?**
Yes

**Is your feature request related to a problem? Please describe.**
Dragonfly today does not expose as many metrics as [redis-exporter](https://github.com/oliver006/redis_exporter/) does on Redis and Valkey.

Additionally, it seems the /metrics endpoint does not show as many metrics as what is available when you instruct redis-exporter to scrape DF via the `INFO ALL` command.

**Describe the solution you'd like**

I would like DF to have observability comparable to Redis/Valkey when that is scraped via the redis-exporter.

**Describe alternatives you've considered**
N/A

**Additional context**
N/A

Start by comparing Dragonfly's /metrics output with the metrics available from INFO ALL through redis-exporter, then review the requested Redis and Valkey metric coverage. Done means the scope is defined and Dragonfly exposes observability comparable to the referenced exporter.

Written by the indexing model from the issue text.