Revise Project Velocity metric

### Name of the Metric Being Revised
[Project Velocity](https://github.com/chaoss/wg-value/blob/main/focus-areas/communal-value/project-velocity.md)

### Metric Items that Were Revised

This metric seems way too focused on OSPOs. Other groups (foundations, in particular) also look at project velocity. I think we should do a re-write of this metric after we finish moving the metrics to the new template.