feat: node refactor (#1316)

* refactor: node reader interface

* refactor: rewrite Taskfile() as anon recursive func

* chore: NewNodeFromIncludedTaskfile

* chore: changelog

taskfile/read/node_base.go

@@ -0,0 +1,18 @@
+package read
+
+// BaseNode is a generic node that implements the Parent() and Optional()
+// methods of the NodeReader interface. It does not implement the Read() method
+// and it designed to be embedded in other node types so that this boilerplate
+// code does not need to be repeated.
+type BaseNode struct {
+	parent   Node
+	optional bool
+}
+
+func (node *BaseNode) Parent() Node {
+	return node.parent
+}
+
+func (node *BaseNode) Optional() bool {
+	return node.optional
+}