Remove some plugins which no longer work
Remove some plugins which no longer work

* They seem abandoned
* Or, at least, they have not been updated to work with 17.x

gocd/www.go.cd,ketan/gocd.github.io,GaneshSPatil/www.go.cd,gocd/www.go.cd,ketan/www.go.cd,nyuday/www.go.cd,gocd/gocd.github.io,ketan/www.go.cd,gocd/www.go.cd,GaneshSPatil/www.go.cd,jyotisingh/www.go.cd,nyuday/www.go.cd,jyotisingh/www.go.cd,gocd/www.go.cd,ketan/gocd.github.io,ketan/www.go.cd,GaneshSPatil/www.go.cd,gocd/gocd.github.io,nyuday/www.go.cd,GaneshSPatil/www.go.cd,gocd/gocd.github.io,ketan/gocd.github.io,gocd/gocd.github.io,jyotisingh/www.go.cd