Add Service Annotations to the DevWorkspaceRouting CRD

[AObuchow]

In order to resolve #1023 we need to allow DevWorkspaceRouting objects to contain annotations which should be applied to the service created for a workspace.

Based on devfile/api#632 (comment), it seems like the service annotations from all of the devworkspace's container components should be aggregated and added as annotations to the workspace's service:

As discussed in today's call, we changed the proposal to have container level annotation defines deployment & service annotation, and move ingress/route annotation to endpoint level.
Since currently we have all containers defined within same pod share the same service. In the future, if we want to have multiple services for a same pod, we can add service annotation to endpoint level, which takes priority to container level service annotation and overwrites it when generating the service resource spec.