Add secrets directory credential resolver

internal/config/config.go

@@ -1,9 +1,14 @@
 package config
 
 type Config struct {
+	Secrets   Secrets    `yaml:"secrets"`
 	Pipelines []Pipeline `yaml:"pipelines"`
 }
 
+type Secrets struct {
+	Directory string `yaml:"directory"`
+}
+
 type Pipeline struct {
 	ID           string           `yaml:"id"`
 	Source       Backend          `yaml:"source"`