chore: Add CPU core count to CPUMetrics

This commit adds the `cores` field to the `CPUMetrics` struct in order to include the number of CPU cores in the collected metrics. This information is useful for understanding the processing power of the server.

InfrastructureAgent/README.md

@@ -70,4 +70,10 @@ sudo ./oneuptime-infrastructure-agent configure --secret-key=YOUR_SECRET_KEY --o
 
 ```bash
 sudo ./oneuptime-infrastructure-agent start
+```
+
+### Stopping the agent
+
+```bash
+sudo ./oneuptime-infrastructure-agent stop
 ```

InfrastructureAgent/model/cpu_metrics.go

@@ -2,4 +2,5 @@ package model
 
 type CPUMetrics struct {
 	PercentUsed float64 `json:"percentUsed"`
+	Cores       int     `json:"cores"`
 }

InfrastructureAgent/utils/cpu.go

@@ -54,8 +54,11 @@ func GetCpuMetrics() *model.CPUMetrics {
 	}
 	cpuUsagePercent := (1 - idleDelta/totalDelta) * 100
 
+	numberOfCpuCores, err := cpu.Counts(true)
+
 	return &model.CPUMetrics{
 		PercentUsed: cpuUsagePercent,
+		Cores:       numberOfCpuCores,
 	}
 }