Use vfsgen instead of go-bindata (#7080)

* use vfsgen instead of go-bindata

* fix templates

* fix fmt

* vendor vsfgen

main.go

@@ -21,6 +21,9 @@ import (
 	_ "code.gitea.io/gitea/modules/markup/markdown"
 	_ "code.gitea.io/gitea/modules/markup/orgmode"
 
+	// for embed
+	_ "github.com/shurcooL/vfsgen"
+
 	"github.com/urfave/cli"
 )