2.2.0 release

2.2.0 release

- move api into dedicated sdc-distribution-client-api maven module [0]
- change package coordinates for `DistributionStatusEnum` and `DistributionActionResultEnum`
  - `org.onap.sdc.utils.DistributionStatusEnum` -> `org.onap.sdc.api.notification.DistributionStatusEnum`
  - `org.onap.sdc.utils.DistributionActionResultEnum` -> `org.onap.sdc.api.results.DistributionActionResultEnum`

[0] this prepares a separate spring boot starter implementation
    with a smaller interface, autoconfiguration and removed runtime
    dependency on sdc-be for the kafka endpoint configuration

Issue-ID: SDC-4777
Change-Id: I74a5f71e20384dad7126b073a7bc6955ef5be4cd
Signed-off-by: Fiete Ostkamp <fiete.ostkamp@telekom.de>