refactor metrics registry and add a system metric

Author: fredr

Cargo.lock

@@ -125,11 +125,11 @@ cookie = "0.18.1"
 malachite = "0.6.1"
 byteorder = "1.5.0"
 metrics = "0.24.2"
-metrics-util = { version = "0.20.0", features = ["registry", "storage"] }
 dashmap = "6.1.0"
 google-cloud-monitoring-v3 = "1.0.0"
 google-cloud-api = "1.0.0"
 google-cloud-wkt = "1.0.0"
+sysinfo = "0.37.2"
 
 [build-dependencies]
 prost-build = "0.12.3"