Implement Prom metrics for Pipelines
Couldn't put it in the title, but what I mean is; we should monitor what the origin is for a pipeline that is created.
Its one of:
- Trigger Request
- Pipeline Schedule
- Mirroring push
- Regular push
This could help us catch abuse and also help us in other decisions. Furthermore, our customers would be getting insight with this data.
/cc @bjk-gitlab