Golangci lint fixes (#195)

* Add golangci-lin as make target
* Fix: could omit type ... from declaration; it will be inferred from the right-hand side (staticcheck)
* Fix func intArrayContains is unused (unused)
* Fix: could use strings.ReplaceAll instead (staticcheck)
* Fix: could expand call to math.Pow (staticcheck)
* Fix: could use tagged switch on `...` (staticcheck)
* Fix: Error return value of `...` is not checked (errcheck)
* Fix: ineffectual assignment to err (ineffassign)
* Fix: There is no need to wait for command completion
* Add cpustat, diskstat and schedstat config
* Use slices to exclude metrics
* Replaced stringArrayContains by slices.Contains
* Replace m[k]=v loop with maps.Copy
* Use module slices from the standard library. Remove use of golang.org/x/exp/slices
* Use SplitSeq and max to modernize code

collectors/numastatsMetric.go

@@ -72,7 +72,9 @@ func (m *NUMAStatsCollector) Init(config json.RawMessage) error {
 
 	m.name = "NUMAStatsCollector"
 	m.parallel = true
-	m.setup()
+	if err := m.setup(); err != nil {
+		return fmt.Errorf("%s Init(): setup() call failed: %w", m.name, err)
+	}
 	m.meta = map[string]string{
 		"source": m.name,
 		"group":  "NUMA",
@@ -186,7 +188,11 @@ func (m *NUMAStatsCollector) Read(interval time.Duration, output chan lp.CCMessa
 				t.previousValues[key] = value
 			}
 		}
-		file.Close()
+		if err := file.Close(); err != nil {
+			cclog.ComponentError(
+				m.name,
+				fmt.Sprintf("Read(): Failed to close file '%s': %v", t.file, err))
+		}
 	}
 }