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/ast/taskrc.go

@@ -0,0 +1,8 @@
+package ast
+
+import "github.com/Masterminds/semver/v3"
+
+type TaskRC struct {
+	Version     *semver.Version `yaml:"version"`
+	Experiments map[string]int  `yaml:"experiments"`
+}