Use vfsgen instead of go-bindata (#7080)

* use vfsgen instead of go-bindata

* fix templates

* fix fmt

* vendor vsfgen

vendor/github.com/shurcooL/vfsgen/doc.go

@@ -0,0 +1,15 @@
+/*
+Package vfsgen takes an http.FileSystem (likely at `go generate` time) and
+generates Go code that statically implements the provided http.FileSystem.
+
+Features:
+
+-	Efficient generated code without unneccessary overhead.
+
+-	Uses gzip compression internally (selectively, only for files that compress well).
+
+-	Enables direct access to internal gzip compressed bytes via an optional interface.
+
+-	Outputs `gofmt`ed Go code.
+*/
+package vfsgen