Add comments to spec.go
Add comments to spec.go

`spec.go` lacks lot of explanation of fields and structs. This commit
adds comments to the file.

cdrage/kedge,ashetty1/kedge,surajnarwade/kedge,surajnarwade/kedge,cdrage/kedge,ashetty1/kedge,cdrage/kedge,kadel/kedge,kedgeproject/kedge,kedgeproject/kedge,kadel/kedge,surajnarwade/kedge,kedgeproject/kedge