Create build status endpoint 

Add a new endpoint in builds to check the status on any build using buildid
`
GET /v1alpha1/builds/{buildId}/status`

**class design**
```
class BuildStatus {
   static enum Status { PENDING, COMPLETED }
   String id
   Status status
   Boolean succeeded
   Instant created
   Duration duration
}
```

cc: @pditommaso @ewels 