small reorg, some improvements, readme updates

- fix hemtt config to copy example
- add measurements table in Readme
- ENTITY COUNTS
  - re add side tags
  - use `side group _x` for units and players
  - fix players_connected and add headless_clients
- get `_allUserInfos = allUsers apply {getUserInfo _x} select {count _x > 0};` from main loop and use in entity counts and player performance

extension/IFXMetrics/internal/settings/settings.go

@@ -0,0 +1,80 @@
+package settings
+
+import (
+	"os"
+
+	"github.com/indig0fox/a3go/a3interface"
+	"github.com/spf13/viper"
+)
+
+type CBAEventHandlerSetting struct {
+	Name        string `json:"name"`
+	Description string `json:"description"`
+	Enabled     bool   `json:"enabled"`
+	Bucket      string `json:"bucket"`
+	Measurement string `json:"measurement"`
+}
+
+var Active *viper.Viper
+
+func init() {
+	Active = viper.New()
+}
+
+func Setup(
+	addonFolder string,
+) error {
+	Active.SetConfigName("ifxmetrics.config")
+	Active.SetConfigType("json")
+	Active.AddConfigPath(addonFolder)
+
+	armaDir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	Active.AddConfigPath(armaDir)
+
+	Active.SetDefault("influxdb", map[string]interface{}{
+		"enabled": false,
+		"host":    "http://localhost:8086",
+		"token":   "",
+		"org":     "",
+	})
+
+	Active.SetDefault("arma3", map[string]interface{}{
+		"refreshRateMs": 2000,
+		"debug":         "true",
+	})
+
+	Active.SetDefault("cbaEventHandlers", []map[string]interface{}{})
+
+	if err := Active.ReadInConfig(); err != nil {
+		if _, ok := err.(viper.ConfigFileNotFoundError); ok {
+			// Config file not found; ignore error if desired
+			a3interface.WriteArmaCallback(
+				"ifxmetrics",
+				":LOG:",
+				"WARN",
+				"Config file not found; using default values.",
+			)
+			return nil
+		} else {
+			// Config file was found but another error was produced
+			a3interface.WriteArmaCallback(
+				"ifxmetrics",
+				":LOG:",
+				"ERROR",
+				err.Error(),
+			)
+			return err
+		}
+	} else {
+		a3interface.WriteArmaCallback(
+			"ifxmetrics",
+			":LOG:",
+			"INFO",
+			"Config file found; using values from config file.",
+		)
+	}
+	return nil
+}