Added ./hack/verify-golint.sh command

Golint detects the coding style mistakes, like missing godocs or wrong func/vars names: https://github.com/golang/lint

The sample output:

```
./pkg/oauth/scope/scope.go:24:1: exported function Split should have comment or be unexported
./pkg/oauth/scope/scope.go:32:1: exported function Join should have comment or be unexported
./pkg/oauth/scope/scope.go:36:1: exported function Covers should have comment or be unexported
./pkg/oauth/server/osinserver/registrystorage/storage.go:19:6: exported type UserConversion should have comment or be unexported
./pkg/oauth/server/osinserver/registrystorage/storage.go:33:1: exported function New should have comment or be unexported
```

There are tons of problems with our codebase right now, but I do believe that golint might be too restrictive, so I don't think we should add it into our CI flow. But it is nice tool to use for development and debugging ;-)