feat: add master keys back

internal/db/models/master-key.go

@@ -0,0 +1,10 @@
+package models
+
+import "github.com/google/uuid"
+
+type MasterKey struct {
+	ID       uuid.UUID `gorm:"type:uuid;default:gen_random_uuid();primaryKey" json:"id"`
+	Key      string    `gorm:"not null"`
+	IsActive bool      `gorm:"default:true"`
+	Timestamped
+}