Add plugin tasks (#651)

pkg/plugin/args.go

@@ -0,0 +1,30 @@
+package plugin
+
+import (
+	"github.com/stashapp/stash/pkg/models"
+)
+
+func findArg(args []*models.PluginArgInput, name string) *models.PluginArgInput {
+	for _, v := range args {
+		if v.Key == name {
+			return v
+		}
+	}
+
+	return nil
+}
+
+func applyDefaultArgs(args []*models.PluginArgInput, defaultArgs map[string]string) []*models.PluginArgInput {
+	for k, v := range defaultArgs {
+		if arg := findArg(args, k); arg == nil {
+			args = append(args, &models.PluginArgInput{
+				Key: k,
+				Value: &models.PluginValueInput{
+					Str: &v,
+				},
+			})
+		}
+	}
+
+	return args
+}