feat: recursive config search (#2166)

* refactor: experiments flags

* refactor: args.Parse

* feat: recursive search for taskrc files

* feat: consolidate some code into new fsext package

* feat: add tests for search and default dir

* fix: linting issues

taskrc/node.go

@@ -0,0 +1,24 @@
+package taskrc
+
+import "github.com/go-task/task/v3/internal/fsext"
+
+type Node struct {
+	entrypoint string
+	dir        string
+}
+
+func NewNode(
+	entrypoint string,
+	dir string,
+) (*Node, error) {
+	dir = fsext.DefaultDir(entrypoint, dir)
+	var err error
+	entrypoint, dir, err = fsext.Search(entrypoint, dir, defaultTaskRCs)
+	if err != nil {
+		return nil, err
+	}
+	return &Node{
+		entrypoint: entrypoint,
+		dir:        dir,
+	}, nil
+}