Rework `dash0 metrics`

[mmanciop]

The dash0 metrics command should be reworked to:

1. dash0 metrics query for similarity with dash0 logs query
2. Use on or more --filter as alternative to --query
3. --query should be renamed to the more descriptive --promql
4. Be gated behind --experimental
5. Have its output formats reworked to be aligned with dash0 logs query