Scrape Dovecot metrics into Prometheus
Summary: Ref T1987
Test Plan:
- Reload prometheus, check targets
- Browse in Prometheus /graph?g0.expr=dovecot_build_info
Reviewers: dereckson
Reviewed By: dereckson
Maniphest Tasks: T1987
Differential Revision: https://devcentral.nasqueron.org/D3388