Feature: Exec action (#7)

* feat: implement exec action

* chore: change logs to trace

* refactor: extract from action

internal/action/macros.go

@@ -0,0 +1,30 @@
+package action
+
+import (
+	"bytes"
+	"text/template"
+)
+
+type Macro struct {
+	TorrentName     string
+	TorrentPathName string
+	TorrentUrl      string
+}
+
+// Parse takes a string and replaces valid vars
+func (m Macro) Parse(text string) (string, error) {
+
+	// setup template
+	tmpl, err := template.New("macro").Parse(text)
+	if err != nil {
+		return "", err
+	}
+
+	var tpl bytes.Buffer
+	err = tmpl.Execute(&tpl, m)
+	if err != nil {
+		return "", err
+	}
+
+	return tpl.String(), nil
+}