Add pipeline definition structs

pipeline.go

@@ -0,0 +1,28 @@
+package main
+
+type PipelineType int
+type PipelineStepType int
+
+const (
+	Image PipelineType = iota
+	Video
+)
+
+const (
+	Resize PipelineStepType = iota
+	Compress
+	Encode
+)
+
+type Pipeline struct {
+	Name           string
+	Type           PipelineType
+	RemoveMetadata bool
+	Steps          []Step
+}
+
+type Step struct {
+	Name string
+	Type PipelineStepType
+}
+