New static configuration loading system.

Co-authored-by: Mathieu Lonjaret <mathieu.lonjaret@gmail.com>

pkg/config/file/fixtures_test.go

@@ -0,0 +1,34 @@
+package file
+
+type bar string
+
+type Yo struct {
+	Foo string
+	Fii string
+	Fuu string
+	Yi  *Yi `label:"allowEmpty"`
+}
+
+func (y *Yo) SetDefaults() {
+	y.Foo = "foo"
+	y.Fii = "fii"
+}
+
+type Yi struct {
+	Foo string
+	Fii string
+	Fuu string
+}
+
+func (y *Yi) SetDefaults() {
+	y.Foo = "foo"
+	y.Fii = "fii"
+}
+
+type Yu struct {
+	Yi
+}
+
+type Ye struct {
+	*Yi
+}