Fix recovery middleware to render gitea style page. (#13857)

* Some changes to fix recovery

* Move Recovery to middlewares

* Remove trace code

* Fix lint

* add session middleware and remove dependent on macaron for sso

* Fix panic 500 page rendering

* Fix bugs

* Fix fmt

* Fix vendor

* recover unnecessary change

* Fix lint and addd some comments about the copied codes.

* Use util.StatDir instead of com.StatDir

Co-authored-by: 6543 <6543@obermui.de>

vendor/github.com/unrolled/render/helpers_pre16.go

@@ -0,0 +1,26 @@
+// +build !go1.6
+
+package render
+
+import (
+	"fmt"
+	"html/template"
+)
+
+// Included helper functions for use when rendering HTML.
+var helperFuncs = template.FuncMap{
+	"yield": func() (string, error) {
+		return "", fmt.Errorf("yield called with no layout defined")
+	},
+	// `block` is deprecated! Use the `partial` below if you need this functionality still.
+	// Otherwise, checkout Go's `block` implementation introduced in 1.6
+	"block": func() (string, error) {
+		return "", fmt.Errorf("block called with no layout defined")
+	},
+	"partial": func() (string, error) {
+		return "", fmt.Errorf("block called with no layout defined")
+	},
+	"current": func() (string, error) {
+		return "", nil
+	},
+}