chore(registry): Upgraded registry to 0.9
fix(*): Handling of unavailable services

Send 503 - Service Temporarily Unavailable for not running services

Fixes #2161
Merge pull request #2443 from johanneswuerbach/no-service

fix(*): Handling of unavailable services
Merge pull request #2439 from johanneswuerbach/registry-upgrade

chore(registry): Upgraded registry to 0.9