add noop store that does nothing

store/noop.go

@@ -0,0 +1,15 @@
+package store
+
+import "github.com/lbryio/lbry.go/v2/stream"
+
+// NoopStore is a store that does nothing
+type NoopStore struct{}
+
+const nameNoop = "noop"
+
+func (n *NoopStore) Name() string                        { return nameNoop }
+func (n *NoopStore) Has(_ string) (bool, error)          { return false, nil }
+func (n *NoopStore) Get(_ string) (stream.Blob, error)   { return nil, nil }
+func (n *NoopStore) Put(_ string, _ stream.Blob) error   { return nil }
+func (n *NoopStore) PutSD(_ string, _ stream.Blob) error { return nil }
+func (n *NoopStore) Delete(_ string) error               { return nil }