Vendor psutils and remove neko

plugins/system/ps/load/load.go

@@ -0,0 +1,16 @@
+package load
+
+import (
+	"encoding/json"
+)
+
+type LoadAvgStat struct {
+	Load1  float64 `json:"load1"`
+	Load5  float64 `json:"load5"`
+	Load15 float64 `json:"load15"`
+}
+
+func (l LoadAvgStat) String() string {
+	s, _ := json.Marshal(l)
+	return string(s)
+}